Chemical liquid supply method and pattern forming method

ABSTRACT

An object of the present invention is to provide a chemical liquid supply method capable of reducing the content of impurities in a chemical liquid. Another object of the present invention is to provide a pattern forming method. 
     The chemical liquid supply method according to an embodiment of the present invention is a chemical liquid supply method of supplying a chemical liquid containing an organic solvent through a pipe line that an apparatus for semiconductor devices comprises, the chemical liquid supply method having a gas pumping step of sending the chemical liquid by pressurization using a gas, in which a moisture content in the gas is 0.00001 to 1 ppm by mass with respect to a total mass of the gas.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of PCT International Application No.PCT/JP2021/031672 filed on Aug. 30, 2021, which claims priority under 35U.S.C. § 119(a) to Japanese Patent Application No. 2020-150403 filed onSep. 8, 2020. The above applications are hereby expressly incorporatedby reference, in their entirety, into the present application.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a chemical liquid supply method and apattern forming method.

2. Description of the Related Art

In a case where semiconductor devices are manufactured by a wiringforming process including photolithography, as a prewet solution, aresist solution, a developer, a rinsing solution, a stripper, a chemicalmechanical polishing (CMP) slurry, a washing solution used after CMP,and the like, a chemical liquid containing a solvent (typically, anorganic solvent) is used. In recent years, semiconductor devicemanufacturing in a node of 10 nm or less has been studied, and there hasbeen a demand for a chemical liquid which has a higher defect inhibitionperformance suppressing the occurrence of defects on a wafer.

In order to obtain such a chemical liquid, it is important to reduce thecontent of impurities in the chemical liquid by precision filtration andto suppress the elution of impurities into the chemical liquid in anapparatus for semiconductor devices.

JP1999-162806A (JP-H11-162806A) describes an invention relating to amanufacturing method of a semiconductor device that supplies a resinsolution by using a pressurized helium gas in forming a resin film by aspin coating method.

SUMMARY OF THE INVENTION

With reference to the method described in JP1999-162806A(JP-H11-162806A), the inventors of the present invention conductedstudies on a supply method having a gas pumping step of sending achemical liquid by pressurization using a gas, among supply methods ofsending a chemical liquid through a pipe line that an apparatus forsemiconductor devices comprises. As a result, the inventors have foundthat there is a room for further improvement on the amount of impuritieseluted into the chemical liquid sent from the pipe line by the gaspumping step.

An object of the present invention is to provide a chemical liquidsupply method capable of reducing the amount of impurities eluted into achemical liquid from a pipe line in a gas pumping step of sending achemical liquid by using a gas. Another object of the present inventionis to provide a pattern forming method.

In order to achieve the above objects, the inventors of the presentinvention carried out intensive examinations. As a result, the inventorshave found that the objects can be achieved by the followingconstitution.

[1]

A chemical liquid supply method of supplying a chemical liquidcontaining an organic solvent through a pipe line that is provided in anapparatus for semiconductor devices, the chemical liquid supply methodhaving a gas pumping step of sending the chemical liquid bypressurization using a gas, in which a moisture content in the gas is0.00001 to 1 ppm by mass with respect to a total mass of the gas.

[2]

The chemical liquid supply method described in [1], in which a purity ofthe gas is 99.9% by volume or more.

[3]

The chemical liquid supply method described in [1] or [2], in which themoisture content in the gas is 0.005 to 0.5 ppm by mass with respect tothe total mass of the gas.

[4]

The chemical liquid supply method described in any one of [1] to [3], inwhich the moisture content in the gas is 0.01 to 0.03 ppm by mass withrespect to the total mass of the gas.

[5]

The chemical liquid supply method described in any one of [1] to [4], inwhich a purity of the gas is 99.999% by volume or more.

[6]

The chemical liquid supply method described in any one of [1] to [5], inwhich the gas includes at least one gas selected from the groupconsisting of nitrogen and argon.

[7]

The chemical liquid supply method described in any one of [1] to [6], inwhich the organic solvent is at least one compound selected from thegroup consisting of propylene glycol monomethyl ether, propylene glycolmonoethyl ether, propylene glycol monopropyl ether, propylene glycolmonomethyl ether acetate, ethyl lactate, methyl methoxypropionate, ethylpropionate, cyclopentanone, cyclohexanone, γ-butyrolactone, diisoamylether, butyl acetate, isoamyl acetate, isopropanol, 4-methyl-2-pentanol,1-hexanol, dimethylsulfoxide, n-methyl pyrrolidone, diethylene glycol,ethylene glycol, dipropylene glycol, propylene glycol, ethylenecarbonate, propylene carbonate, sulfolane, cycloheptanone, 2-heptanone,methyl ethyl ketone, hexane, and a combination of these.

[8]

A chemical liquid preparation step of chemical liquid supply methoddescribed in any one of [1] to [7], further having a chemical liquidpreparation step of preparing the chemical liquid in a storage tank thatis in communication with the pipe line, in which the gas pumping step isa step of sending the chemical liquid from the storage tank through thepipe line by introducing the gas into the storage tank.

[9]

The chemical liquid supply method described in any one of [1] to [8],further having a purification step of filtering the chemical liquid sentby the gas pumping step by using a filter.

[10]

The chemical liquid supply method described in [9], in which a totalcontent of a Fe component, a Cr component, a Ni component, and an Alcomponent in the chemical liquid filtered by the purification step is0.04 to 1,200 ppt by mass with respect to a total mass of the chemicalliquid.

[11]

The chemical liquid supply method described in [9] or [10], in which atotal content of a Fe component, a Cr component, a Ni component, and anAl component in the chemical liquid filtered by the purification step is0.2 to 400 ppt by mass with respect to a total mass of the chemicalliquid.

[12]

The chemical liquid supply method described in any one of [9] to [11],in which a total content of a Fe component, a Cr component, a Nicomponent, and an Al component in the chemical liquid filtered by thepurification step is 0.2 to 60 ppt by mass with respect to aa total massof the chemical liquid.

[13]

The chemical liquid supply method described in any one of [9] to [12],in which a moisture content in the chemical liquid filtered by thepurification step is 0.0005% to 0.03% by mass with respect to a totalmass of the chemical liquid.

[14]

The chemical liquid supply method described in any one of [9] to [13],in which a moisture content in the chemical liquid filtered by thepurification step is 0.001% to 0.02% by mass with respect to a totalmass of the chemical liquid.

[15]

The chemical liquid supply method described in any one of [9] to [14],in which a moisture content in the chemical liquid filtered by thepurification step is 0.001% to 0.01% by mass with respect to a totalmass of the chemical liquid.

[16]

The chemical liquid supply method described in any one of [9] to [15],in which a content of dioctyl phthalate in the chemical liquid filteredby the purification step is 0.001 to 10 ppb by mass with respect to atotal mass of the chemical liquid.

[17]

The chemical liquid supply method described in any one of [9] to [16],in which a content of dioctyl phthalate in the chemical liquid filteredby the purification step is 0.01 to 5 ppb by mass with respect to atotal mass of the chemical liquid.

[18]

The chemical liquid supply method described in any one of [9] to [17],in which a content of dioctyl phthalate in the chemical liquid filteredby the purification step is 0.01 to 1 ppb by mass with respect to atotal mass of the chemical liquid.

[19]

The chemical liquid supply method described in any one of [1] to [18],further having a gas purification step of purifying a raw material gasby using a gas filter, in which the gas purified by the gas purificationstep is used in the gas pumping step.

[20]

A pattern forming method having a pre-wetting step of bringing a pre-wetliquid into contact with a substrate, a resist film forming step offorming a resist film on the substrate by using a resist composition, astep of exposing the resist film, a development step of developing theexposed resist film by using a developer to form a resist pattern, and arinsing step of bringing a rinsing liquid into contact with thesubstrate on which the resist pattern is formed, in which at least oneliquid selected from the group consisting of the pre-wet liquid, thedeveloper, and the rinsing liquid is the chemical liquid supplied by thesupply method described in any one of [1] to [19].

According to the present invention, it is possible to provide a chemicalliquid supply method capable of reducing the amount of impurities elutedinto a chemical liquid from a pipe line in a gas pumping step of sendinga chemical liquid by using a gas. In addition, according to the presentinvention, it is possible to provide a pattern forming method.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view showing an example of an apparatus used for achemical liquid supply method.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, the present invention will be specifically described.

The following configuration requirements will be described based ontypical embodiments of the present invention in some cases, but thepresent invention is not limited to the embodiments.

In the present specification, a range of numerical values describedusing “to” means a range including the numerical values listed beforeand after “to” as a lower limit and an upper limit respectively.

In the present specification, in a case where there are two or morekinds of components corresponding to a certain component, “content” ofsuch a component means the total content of the two or more kinds ofcomponents.

In the present specification, “preparation” means not only thepreparation of a specific material by means of synthesis or mixing butalso the preparation of a predetermined substance by means of purchaseand the like.

In the present specification, “ppm” means “parts-per-million (10⁻⁶)”,“ppb” means “parts-per-billion (10⁻⁹)”, and “ppt” means“parts-per-trillion (10⁻¹²)”.

Furthermore, in the present specification, “radiation” means, forexample, far ultraviolet, extreme ultraviolet (EUV), X-rays, electronbeams, and the like. In addition, in the present specification, lightmeans actinic rays or radiation. In the present specification, unlessotherwise specified, “exposure” includes not only exposure by farultraviolet, X-rays, EUV, and the like, but also lithography by particlebeams such as electron beams or ion beams.

[Chemical Liquid Supply Method]

The chemical liquid supply method according to an embodiment of thepresent invention (hereinafter, also simply called “the present supplymethod”) is a method of supplying a chemical liquid containing anorganic solvent through a pipe line that an apparatus for semiconductordevices comprises. The present supply method is characterized in thatthe method has a gas pumping step of sending a chemical liquid through apipe line by pressurization using a gas, and that a moisture content inthe gas is 0.01 to 1 ppm by mass with respect to a total mass of thegas.

Details of the mechanism through which the chemical liquid supply methodreduces the amount of impurities eluted into the chemical liquid fromthe pipe line are unclear. According to the inventors of the presentinvention, presumably, performing the gas pumping step by using a gashaving a moisture content reduced to a specific range may keep thecontent of moisture mixed into the chemical liquid from the gas low,which may suppress the elution and/or mixing of impurities into thechemical liquid from liquid contact portions of the pipe line and othermembers while allowing the moisture content in the gas to be equal to ormore than a predetermined lower limit. The inventors assume that as aresult, a trace of moisture may be mixed into the chemical liquid fromthe gas, which may suppress electrostatic destruction inducing theelution of impurities in liquid contact portions of the pipe line andother members.

Hereinafter, regarding the present invention, being excellentlyeffective for reducing the amount of impurities eluted into the chemicalliquid from the pipe line in the gas pumping step will be also describedas “the effect of the present invention is excellent”.

First, a supply device used in the present supply method will bedescribed, and then each step of the present supply method will bedescribed.

[Supply Device]

The supply device (hereinafter, also simply called “supply device”) usedin the present supply method is a device for semiconductor devices. Inthe present specification, “for semiconductor devices” means that thedevice is used for manufacturing of semiconductor devices.

The supply device may be a device that constitutes a part of a knownsemiconductor device manufacturing apparatus or a known semiconductordevice treatment apparatus, and is preferably a device incorporated intoa coater developer.

The supply device will be described with reference to a drawing. FIG. 1is a schematic view showing an example of the configuration of thepresent device.

A supply device 10 shown in FIG. 1 is a device for semiconductordevices, and comprises a storage tank 11, a gas pipe 12, a pipe line 13,an intermediate tank 14, a pipe line 15, a discharge unit 16, a pump 17and a filter unit 20 disposed on the pipe line 15, and a gas filter 21disposed on the gas pipe 12.

In FIG. 1 , F₁ and F₂ represent the moving direction of a liquid(chemical liquid) in the supply device 10, and G represents the movingdirection of a pumping gas in the supply device 10.

The storage tank 11 is a container having a function of storing achemical liquid. The storage tank 11 is connected to the gas pipe 12 andthe pipe line 13 that penetrate the top of the storage tank 11 and arein communication with the inside of the storage tank 11. In addition,the storage tank 11 is provided with a chemical liquid introduction port(not shown in the drawing) for introducing a chemical liquid.

The gas pipe 12 is connected to a gas supply portion, which is not shownin the drawing, and the storage tank 11. As shown by an arrow G, the gassent from the gas supply portion passes through the inside of the gaspipe 12 and is introduced into the storage tank 11 from a gasintroduction port 12 a disposed near the top of the storage tank 11.

The gas filter 21 is a filter that is disposed on the gas pipe 12 andhas a function of removing moisture and/or impurities contained in thegas flowing in the gas pipe 12.

The pipe line 13 is connected to the storage tank 11 and theintermediate tank 14. An upstream end part of the pipe line 13penetrates the top of the storage tank 11 and extends to the vicinity ofthe bottom of the storage tank 11. A downstream end part of the pipeline 13 penetrates the top of the intermediate tank 14 and extends tothe upper part of the intermediate tank 14.

The chemical liquid stored in the storage tank 11 is sent to theintermediate tank 14 through the pipe line 13 as shown by the arrow F₁.As will be described later, the chemical liquid is sent by a gas pumpingstep of introducing a pumping gas into the storage tank 11 to pressurizethe chemical liquid.

In the present specification, unless otherwise specified, the term “pipeline” means all parts in which the chemical liquid can exist between thestorage tank 11 and the discharge unit 16.

The intermediate tank 14 is a container having a function of temporarilystoring the chemical liquid sent from the storage tank 11. A pipe line15 that is in communication with the discharge unit 16 is connected tothe bottom of the intermediate tank 14.

As shown by the arrow F₂, the chemical liquid stored in the intermediatetank 14 is discharged from the discharge unit 16 through the pipe line15. The pump 17 provided on the pipe line 15 has a function of sendingthe chemical liquid stored in the intermediate tank 14 to the dischargeunit 16.

A filter cartridge having a filter is housed in the filter unit 20. Thefilter unit 20 has a function of filtering the chemical liquid passingthrough the pipe line 15 by using a filter. As the filter and filtercartridge constituting the filter unit 20, known filters and filtercartridges can be used. Details of the filter included in the filterunit will be explained in a purification step that will be describedlater.

The chemical liquid supplied by the supply device 10 is discharged fromthe discharge unit 16. The use of the discharged chemical liquid is notparticularly limited. In a case where the discharge unit 16 has afunction of jetting the chemical liquid, the chemical liquid may bejetted from the discharge unit 16 onto a wafer to perform varioustreatments, or the discharge unit 16 may be connected to a storagecontainer for transporting and/or storing the chemical liquid such thatthe storage container is filled with the chemical liquid.

The material constituting the storage tank 11 and the intermediate tank14 (hereinafter, both of these will be also simply collectively called“container”) that the supply device 10 comprises is not particularlylimited, and may be an organic substance, an inorganic substance, or acombination of these. Specific examples of the material include a resin,glass, a metal, or a composite material of these (for example, amaterial composed of a metal base material and a glass or resin lining).The material can be arbitrarily selected from these depending on thetype of chemical liquid to be accommodated. Particularly, it ispreferable that at least a part of the liquid contact portion of thecontainer (more preferably the entirety of the liquid contact portionand even more preferably the entirety of the container) contain ananticorrosive material, which will be described later, as a component.

For example, in a case where the container contains an anticorrosivematerial as a material component, examples of the form where at least apart of the liquid contact portion of the container contains ananticorrosive material as a component include a case where the containeris a lining container having a base material and a coating layer(lining) which is disposed on the base material and contains ananticorrosive material as a material component (in this case, the basematerial may also contain an anticorrosive material as a materialcomponent), and the like.

More specifically, examples thereof include a container made ofstainless steel, which will be described later, a container made ofpolytetrafluoroethylene, a lining container composed of a base materialthat consists of stainless steel and a coating layer that consists ofpolytetrafluoroethylene and is on the inner wall surface of the basematerial, and the like.

“Liquid contact portion” refers to a portion of the container that islikely to come into contact with the chemical liquid contained in thecontainer.

The anticorrosive material is at least one kind of material selectedfrom the group consisting of a nonmetal material and a metal material.As the metal material, an electropolished metal material is preferable.

As the nonmetal material, known materials can be used without particularlimitation.

Examples of the nonmetal material include a polyolefin-based resin suchas a polyethylene resin, a polypropylene resin, or apolyethylene-polypropylene resin; a fluorine-containing resin such as atetrafluoroethylene resin, a tetrafluoroethylene-perfluoroalkyl vinylether copolymer, a tetrafluoroethylene-hexafluoropropylene copolymerresin, a tetrafluoroethylene-ethylene copolymer resin, achlorotrifluoroethylene-ethylene copolymer resin, a vinylidene fluorideresin, a chlorotrifluoroethylene copolymer resin, or a vinyl fluorideresin, and the like. Among these, a fluorine-containing resin ispreferable, and polytetrafluoroethylene (PTFE) is more preferable.

As the metal material, known materials can be used without particularlimitation.

Examples of the metal material include a metal material in which thetotal content of chromium and nickel is greater than 25% by mass withrespect to the total mass of the metal material. The total content ofchromium and nickel is more preferably 30% by mass or more. The upperlimit of the total content of chromium and nickel in the metal materialis not particularly limited, but is preferably 90% by mass or less ingeneral.

Examples of the metal material include stainless steel, carbon steel,alloyed steel, nickel chromium molybdenum steel, chromium steel,chromium molybdenum steel, manganese steel, and nickel chromium alloy.Among these, stainless steel is preferable.

As the stainless steel, known stainless steel can be used withoutparticular limitation. Among these, an alloy with a nickel content of 8%by mass or more is preferable, and austenite-based stainless steel witha nickel content of 8% by mass or more is more preferable. Examples ofthe austenite-based stainless steel include Steel Use Stainless (SUS)304 (Ni content: 8% by mass, Cr content: 18% by mass), SUS304L (Nicontent: 9% by mass, Cr content: 18% by mass), SUS316 (Ni content: 10%by mass, Cr content: 16% by mass), and SUS316L (Ni content: 12% by mass,Cr content: 16% by mass).

As the nickel-chromium alloy, known nickel-chromium alloys can be usedwithout particular limitation. Among these, a nickel-chromium alloy ispreferable in which the nickel content is 40% to 75% by mass and thechromium content is 1% to 30% by mass.

Examples of the nickel-chromium alloy include HASTELLOY (trade name, thesame is true of the following description), MONEL (trade name, the sameis true of the following description), and INCONEL (trade name, the sameis true of the following description). More specifically, examplesthereof include HASTELLOY C-276 (Ni content: 63% by mass, Cr content:16% by mass), HASTELLOY C (Ni content: 60% by mass, Cr content: 17% bymass), and HASTELLOY C-22 (Ni content: 61% by mass, Cr content: 22% bymass).

Furthermore, as necessary, the nickel-chromium alloy may further containat least one element selected from the group consisting of boron,silicon, tungsten, molybdenum, copper, and cobalt, in addition to theaforementioned alloy.

The method of electropolishing the metal material is not particularlylimited, and examples thereof include the methods described inparagraphs “0011” to “0014” of JP2015-227501A, paragraphs “0036” to“0042” of JP2008-264929A, and the like.

Presumably, in a case where the metal material is electropolished, thechromium content in a passive layer on the surface thereof may becomehigher than the chromium content in the parent phase. Presumably, as aresult, from a device where the liquid contact portion is formed of anelectropolished metal material, a metal component containing metal atomsis unlikely to be eluted into the chemical liquid, which may make itpossible to prepare a chemical liquid with a lower impurity content.

The metal material may have undergone buffing. As the buffing method,known methods can be used without particular limitation. The size ofabrasive grains used for finishing the buffing is not particularlylimited, but is preferably #400 or less because such grains make it easyto further reduce the surface asperity of the metal material. Thebuffing is preferably performed before the electropolishing.

The material constituting the pipe line 13 and the pipe line 15 that thesupply device 10 comprises is not particularly limited, and a known pipecan be used. Examples of the pipe include a form comprising a pipe, apump, a valve, and the like.

It is preferable that the liquid contact portion of the pipe lines 13and 15 be formed of the anticorrosive material described above.

The supply device that can be used in the present supply method is notlimited to the supply device 10 having the configuration describedabove. The supply device that can be used in the present supply methodmay have a configuration other than the configuration described above.

For example, although the supply device 10 shown in FIG. 1 comprisesonly one filter unit 20 on the pipe line 15, the supply device mayinclude a plurality of filters. In this case, the plurality of filtersthat the supply device comprises may be arranged in series or arrangedin a row in the chemical liquid transfer direction.

The supply device 10 shown in FIG. 1 has a configuration in which thepurified chemical liquid that has flowed out of the filter unit 20 istransferred to the discharge unit 16. However, the supply device mayhave a configuration in which the chemical liquid that has flowed out ofthe filter unit 20 is sent back to the intermediate tank 14 and passthrough the filter unit 20 again. This filtration method is calledcirculation filtration.

From the viewpoint of productivity and from the viewpoint of inhibitingimpurities and the like captured by the filter from being mixed into thechemical liquid again, it is preferable that the chemical liquid bepassed through the filter only once without being subjected tocirculation filtration.

Although the filter unit 20 included in the supply device 10 comprises afilter and a filter cartridge, a filter that is not accommodated in thefilter cartridge may also be used. The supply device may have, forexample, an aspect in which the chemical liquid is passed through afilter in the form of a flat plate.

The supply device may comprise one filter or a plurality of filters onthe pipe line connecting the storage tank and the intermediate tank. Ina case where the supply device comprises a plurality of filters, theplurality of filters may be arranged in series or arranged in a row inthe chemical liquid transfer direction. In the supply device, thechemical liquid may be passed only once through the filter provided onthe pipe line connecting the storage tank and the intermediate tank.Alternatively, a return path for returning the chemical liquid from thedownstream side of the filter to the storage tank may be provided, andthe chemical liquid may be passed through the filter multiple times.

The supply device may not comprise a filter. In view of making itpossible to further reduce the content of impurities in the chemicalliquid, in the present supply method, it is preferable that a chemicalliquid purification step, which will be described later, be performedusing a supply device comprising a filter.

Next, each step of the present supply method will be described byexemplifying an embodiment in which the present supply method isperformed using the supply device 10 shown in FIG. 1 .

[Chemical Liquid Preparation Step]

First, a chemical liquid preparation step of introducing the chemicalliquid to be supplied by the present supply method into the storage tank11 is performed.

<Chemical Liquid>

The chemical liquid supplied by the present supply method is notparticularly limited as long as the chemical liquid contains an organicsolvent. It is possible to use known chemical liquids used for atreatment such as manufacturing of a semiconductor device.

(Organic Solvent)

The chemical liquid contains an organic solvent. The content of theorganic solvent in the chemical liquid is not particularly limited. Thecontent of the organic solvent with respect to the total mass of thechemical liquid is preferably 98% by mass or more, more preferably 99%by mass or more, and even more preferably 99.9% by mass or more. Theupper limit of thereof is not particularly limited, but is preferably99.999% by mass or less.

One kind of organic solvent may be used singly, or two or more kinds oforganic solvents may be used in combination. In a case where two or morekinds of organic solvents are used in combination, the total contentthereof is preferably within the above range.

In the present specification, an organic solvent means one liquidorganic compound which is contained in the chemical liquid in an amountgreater than 10,000 ppm by mass with respect to the total mass of thechemical liquid. That is, in the present specification, a liquid organiccompound contained in an amount greater than 10,000 ppm by mass withrespect to the total mass of the chemical liquid corresponds to anorganic solvent.

In the present specification, “liquid” means that the compound stays inliquid form at 25° C. under atmospheric pressure.

The type of organic solvent is not particularly limited, and knownorganic solvents can be used.

Examples of the organic solvent include polar organic solvents such asalkylene glycol monoalkyl ether carboxylate, alkylene glycol monoalkylether, a lactic acid alkyl ester, alkyl alkoxypropionate, cyclic lactone(preferably having 4 to 10 carbon atoms), a monoketone compound whichmay have a ring (preferably having 4 to 10 carbon atoms), alkylenecarbonate, alkoxyalkyl acetate, and alkyl pyruvate, and nonpolar organicsolvents such as an unsubstituted liquid hydrocarbon.

Examples of the unsubstituted liquid hydrocarbon include linear,branched, or cyclic substituted hydrocarbons having 5 to 12 carbonatoms. As such hydrocarbons, n-pentane, n-hexane, n-heptane, n-octane,and n-nonane, n-decane, n-undecane, n-dodecane, isopentane, neopentane5-ethyl-3-methyloctane, cyclopentane, cyclohexane, methylcyclopentane,1-ethyl-3-methylcyclohexane, or a combination of these preferable, andn-hexane is more preferable.

Furthermore, as the organic solvent, those described in JP2016-057614A,JP2014-219664A, JP2016-138219A, and JP2015-135379A may be used.

As the organic solvent, propylene glycol monomethyl ether (PGMM),propylene glycol monoethyl ether (PGME), propylene glycol monopropylether (PGMP), propylene glycol monomethyl ether acetate (PGMEA), ethyllactate (EL), methyl methoxypropionate (MPM), ethyl propionate,cyclopentanone (CyPn), cyclohexanone (CyHe), γ-butyrolactone (γBL),diisoamyl ether (DIAE), butyl acetate (nBA), isoamyl acetate (iAA),isopropanol (IPA), 4-methyl-2-pentanol (MIBC), 1-hexanol,dimethylsulfoxide (DMSO), n-methyl-2-pyrrolidone (NMP), diethyleneglycol (DEG), ethylene glycol (EG), dipropylene glycol (DPG), propyleneglycol (PG), ethylene carbonate (EC), propylene carbonate (PC),sulfolane, cycloheptanone, 2-heptanone (MAK), methyl ethyl ketone (MEK),hexane, or a combination of these is preferable.

Among these, PGMEA, ethyl propionate, CyPn, CyHe, nBA, iAA, MAK, MEK,propylene carbonate, hexane, or a combination of these is morepreferable.

The type and content of the organic compound (including an organicsolvent and an organic impurity which will be described later) containedin the chemical liquid can be measured using gas chromatography-massspectroscopy (GC-MS). The measurement conditions are as described inExamples.

The chemical liquid may contain other components in addition to theabove components. Examples of the other components include an organicimpurity, water, and a metal component.

(Organic Impurity)

The chemical liquid may contain an organic impurity. The content of theorganic impurity in the chemical liquid is not particularly limited. Thecontent of the organic impurity with respect to the total mass of thechemical liquid is preferably 10,000 ppm by mass or less, and morepreferably 1,000 ppm by mass or less. The lower limit thereof is notparticularly limited, but is preferably 0.1 ppm by mass or more.

In the present specification, an organic impurity means an organiccompound that is different from an organic solvent contained in thechemical liquid and contained in the chemical liquid at a content of10,000 ppm by mass or less with respect to the total mass of thechemical liquid. That is, in the present specification, an organiccompound contained in the chemical liquid at a content of 10,000 ppm bymass or less with respect to the total mass of the chemical liquidcorresponds to an organic impurity and does not correspond to an organicsolvent.

In a case where each of a plurality of organic compounds is contained inthe chemical liquid at a content of 10,000 ppm by mass or less withrespect to the total mass of the chemical liquid, each of the pluralityof organic compounds corresponds to an organic impurity.

In many cases, the organic impurity is mixed into or added to thechemical liquid in the process of synthesizing, purifying, and/ortransferring the organic solvent to be incorporated into the chemicalliquid. Examples of such an organic impurity include a plasticizer, anantioxidant, and a compound derived from these (for example, adecomposition product).

In the process of synthesizing and purifying an organic solvent,sometimes a plasticizer is eluted into the organic solvent from theliquid contact portion of each unit (a reaction section, a distillationcolumn, a filter unit, or the like) of the device (purification device)used for the purification.

In addition, in a case where an antioxidant is intentionally added to anorganic solvent or in a case where a commercially available organicsolvent is purchased and used, sometimes the organic solvent containsthe antioxidant mixed in.

Among the organic impurities of these components, an organic impurityhaving a high boiling point (hereinafter, also described as“high-boiling-point organic impurity”) readily volatilizes, thus easilyremains on the substrate surface as particles of organic residues, andis likely to cause defects in a semiconductor device.

Therefore, in the chemical liquid, the content of the high-boiling-pointorganic impurity (particularly, an organic impurity having a boilingpoint of 250° C. or higher) with respect to the total mass of thechemical liquid is preferably 1 ppm by mass or less, more preferably 50ppb by mass or less, and even more preferably 10 ppb by mass or less.The lower limit thereof is not particularly limited, but is preferably10 ppt by mass or more.

Examples of the high-boiling-point organic impurity include dioctylphthalate (DOP, boiling point 385° C.), diisononyl phthalate (DINP,boiling point 403° C.), dioctyl adipate (DOA, boiling point 335° C.),dibutyl phthalate (DBP, boiling point 340° C.), and ethylene propylenerubber (EPDM, boiling point 300° C. to 450° C.).

Particularly, in view of further improving the impurity removingperformance of the filter used in the purification step that will bedescribed later, in the chemical liquid, the content of dioctylphthalate (DOP) with respect to the total mass of the chemical liquid ispreferably 0.001 to 10 ppb by mass, more preferably 0.01 to 5 ppb bymass, and even more preferably 0.01 to 1 ppb by mass.

(Metal Component)

The chemical liquid may contain a metal component.

In the present specification, “metal component” consists of a metalpresent as particles in the chemical liquid (that is, “metal particles”)and a metal present as ions in the chemical liquid (that is, “metalions”).

The metal particles also mean, in addition to particles consist of asimple metal or an alloy, a compound composed of a metal, such as anoxide, a sulfide, or the like of a simple metal or an alloy, and anothernon-metal element bonded to the metal.

The metal ions mean simple metal ions and complex ions (for example, anammine complex, a cyano complex, a halogeno complex, a hydroxyl complex,and the like).

In the present specification, in a case where the there is a metalcomponent (metal particles and metal ions) containing a certain metalelement M, “content of the metal component” means the content of onlythe metal component containing the metal element M.

In a case where the metal component contains two or more kinds of metalelements, the content of only a metal element having the highest contentis calculated as the content of the metal component. That is, thecontent of a metal component containing two or more kinds of metalelements is not included the contents of two or more kinds of metalcomponents in duplicate. More specifically, the content of a metalcomponent containing Fe and Cr is not included in both the content ofthe Fe component and the content of the Cr component.

In the present specification, “content of an Fe component” refers to thetotal content of metal particles (Fe particles) having the highest Fecontent among the metal elements and metal ions (Fe ions) having thehighest Fe content among the metal elements. “Content of a Cr component”refers to the total content of metal particles (Cr particles) having thehighest Cr content among the metal elements and metal ions (Cr ions)having the highest Cr content among the metal elements. “Content of a Nicomponent” refers to the total content of metal particles (Ni particles)having the highest Ni content among the metal elements and metal ions(Ni ions) having the highest Ni content among the metal elements.“Content of an Al component” refers to the total content of metalparticles (Al particles) having the highest Al content among the metalelements and metal ions (Al ions) having the highest Al content amongthe metal elements.

In view of further improving the impurity removing performance of thefilter used in the purification step which will be described later, inthe chemical liquid, the total content of the Fe component, the Crcomponent, the Ni component, and the Al component (hereinafter, thesecomponents will be also called “specific metal components”) with respectto the total mass of the chemical liquid is preferably 0.04 to 1,200 pptby mass, more preferably 0.2 to 400 ppt by mass, and even morepreferably 0.2 to 60 ppt by mass.

Presumably, the impurity removal performance of the filter may beimproved for the following reason. That is, in a case where the totalcontent of the specific metal components in the chemical liquid is equalto or less than the aforementioned upper limit, static electricity islikely to be accumulated in the filter, and the removal performance ofthe filter may be improved. In contrast, in a case where the totalcontent of the specific metal components is equal to or more than theaforementioned lower limit, electrostatic destruction in the liquidcontact portion of the filter is suppressed, and the removal performanceof the filter may be improved.

The total content of all the metal components in the chemical liquid ispreferably 5,000 ppt by mass (5 ppb by mass) or less, and morepreferably 500 ppt by mass or less. The lower limit is not particularlylimited, and may be equal to or less than the detection limit.

In the chemical liquid, the content of a metal component other than thespecific metal components per metal element is preferably 50 ppt by massor less, and more preferably 10 ppt by mass or less. The lower limit isnot particularly limited. The lower limit may be equal to or less thanthe detection limit, and is preferably 0.001 ppt by mass or more.

The type and content of the metal component in the chemical liquid canbe measured by the Single Nano Particle Inductively Coupled Plasma MassSpectrometry (SP-ICP-MS).

The device used in SP-ICP-MS is the same as the device used in generalinductively coupled plasma mass spectrometry (ICP-MS). The onlydifference between SP-ICP-MS and ICP-MS is how to analyze data. WithSP-ICP-MS, data can be analyzed using commercial software.

With ICP-MS, the content of a metal component as a measurement target ismeasured regardless of the way the metal component is present.Accordingly, the total mass of metal particles and metal ions as ameasurement target is quantified as the content of the metal component.

The type and content of the metal component in the chemical liquid canbe measured by the method described in Examples, by using, for example,Agilent 8800 triple quadrupole inductively coupled plasma massspectrometry (ICP-MS, for semiconductor analysis, option #200)manufactured by Agilent Technologies, Inc. as a device for SP-ICP-MS.

(Water)

The chemical liquid may contain water.

The moisture content (content of water) in the chemical liquid is notparticularly limited. In view of further improving the removalperformance of the filter used in the purification step which will bedescribed later, the moisture content with respect to the total mass ofthe chemical liquid is preferably 0.0005% to 0.03% by mass, morepreferably 0.001% to 0.02% by mass, and even more preferably 0.001% to0.01% by mass.

Presumably, the removal performance of the filter may be improved forthe following reason. That is, in a case where the moisture content inthe chemical liquid is equal to or less than the aforementioned upperlimit, the amount of metal components eluted into the chemical liquidfrom a member such as a pipe line is reduced, electricity is likely tobe accumulated in the filter, and the removal performance of the filtermay be improved. In contrast, in a case where the moisture content isequal to or more than the aforementioned lower limit, electrostaticdestruction in the liquid contact portion of the filter is suppressed,and the removal performance of the filter may be improved.

The content of water in the chemical liquid means the content ofmoisture measured using a device which adopts the Karl Fischer titrationmethod as the principle of measurement.

<Preparation of Chemical Liquid>

The method of preparing the aforementioned chemical liquid is notparticularly limited. However, in order to prepare a chemical liquidhaving an organic impurity content, a metal component content, and awater content in a desired range, it is preferable to prepare thechemical liquid by performing the following purification step on aliquid to be purified containing an organic solvent.

There is no particular limit on the timing of performing thepurification step. The purification step may be performed before orafter the manufacturing of the organic solvent contained in the chemicalliquid. In a case where the chemical liquid contains two or more kindsof organic solvents, the organic solvents may be mixed together afterbeing separately purified or may be purified after being mixed together.

The purification step may be performed before or after two or more kindsof the organic solvents are mixed together. The purification step may beperformed only once, or may be performed twice or more.

An example of the purification step will be shown below. In thefollowing description, “liquid to be purified” is a purification targetin the purification step.

Examples of the purification step include an ion exchange treatment ofperforming an ion exchange treatment on the liquid to be purified, adehydration treatment of dehydrating the liquid to be purified, anorganic impurity-removing treatment of removing organic impurities ofthe liquid to be purified, and a filtering treatment using a metal ionadsorption member for the purpose of removing metal ions.

With the ion exchange treatment, it is possible to remove an ioncomponent (for example, a metal component or the like) in the liquid tobe purified.

In the ion exchange treatment, ion exchange means such as an ionexchange resin is used. The ion exchange resin may be any of a cationexchange resin or an anion exchange resin provided in the form of asingle bed, a cation exchange resin and an anion exchange resin providedin the form of a double bed, and a cation exchange resin and an anionexchange resin provided in the form of a mixed bed.

As the ion exchange resin, in order to reduce the elution of moisturefrom the ion exchange resin, it is preferable to use a dry resincontaining as little water as possible. As such a dry resin,commercially available products can be used. Examples thereof include15JS-HG⋅DRY (trade name, dry cation exchange resin, moisture content of2% or less) manufactured by ORGANO CORPORATION), and MSPS2-1⋅DRY (tradename, mixed-bed resin, moisture content of 10% or less).

With the dehydration treatment, it is possible to remove water in theliquid to be purified. In a case where zeolite (particularly, amolecular sieve (trade name) manufactured by UNION SHOWA K.K.), whichwill be described later, or the like is used in the dehydrationtreatment, olefins can also be removed.

Examples of dehydration means used in the dehydration treatment includea dehydrating film, water adsorbent insoluble in a liquid to bepurified, an aerating purge device using a dried inert gas, a heating orvacuum heating device, and the like.

In a case where a dehydrating film is used, membrane dehydration bypervaporation (PV) or vapor permeation (VP) is performed. Thedehydrating film is composed as, for example, a water-permeable filmmodule. As the dehydrating film, it is possible to use films consistingof polymer-based materials, such as a polyimide-based material, acellulose-based material, and a polyvinyl alcohol-based material, or aninorganic material such as a zeolite.

The water adsorbent is used by being added to the liquid to be purified.Examples of the water adsorbent include zeolite, diphosphorus pentoxide,silica gel, calcium chloride, sodium sulfate, magnesium sulfate,anhydrous zinc chloride, fuming sulfuric acid, and soda lime.

With the organic impurity-removing treatment, it is possible to removehigh-boiling-point organic impurity and the like (including organicsubstances having a boiling point of 300° C. or higher) contained in theliquid to be purified.

The organic impurities can be removed by organic impurity-removingmeans, for example, an organic impurity adsorption member provided withan organic impurity adsorption filter capable of adsorbing organicimpurities. In many cases, the organic impurity adsorption membercomprises the aforementioned organic impurity adsorption filter and asubstrate on which the impurity adsorption filter is fixed.

From the viewpoint of improving the organic impurity adsorptionperformance, it is preferable that the organic impurity adsorptionfilter has the skeleton of an organic substance, which can interact withthe organic impurities, on the surface thereof (in other words, it ispreferable that the surface of the organic impurity adsorption filter ismodified with the skeleton of an organic substance which can interactwith the organic impurities). One of the examples of “has the skeletonof an organic substance, which can interact with the organic impurities,on the surface thereof” include a form in which the skeleton of anorganic substance which can interact with the organic impurities isprovided on the surface of a substrate constituting the organic impurityadsorption filter that will be described later.

Examples of the skeleton of an organic substance which can interact withthe organic impurity include a chemical structure which can react withthe organic impurities to make the organic impurities captured by theorganic impurity adsorption filter. More specifically, in a case wherethe organic impurities include dioctyl phthalate, diisononyl phthalate,dioctyl adipate, or dibutyl phthalate, examples of the organic skeletoninclude a benzene ring skeleton. In addition, in a case where theorganic impurities include ethylene propylene rubber, examples of theskeleton of an organic substance include an alkylene skeleton.Furthermore, in a case where the organic impurities include a long-chainn-alkyl alcohol (corresponding to a structural isomer in a case wherethe long-chain 1-alkyl alcohol is used as a solvent), examples of theskeleton of an organic substance include an alkyl group.

Examples of the substrate (material) of organic impurity adsorptionfilter include cellulose supporting activated carbon, diatomite, nylon,polyethylene, polypropylene, polystyrene, and a fluororesin.

Furthermore, as an organic impurity-removing filter, it is also possibleto use a filter prepared by fixing activated carbon to nonwoven fabricdescribed in JP2002-273123A and JP2013-150979A.

The organic impurity-removing treatment is not limited to theaforementioned aspect in which the organic impurity adsorption filtercapable of adsorbing organic impurities is used, and may be, forexample, an aspect in which organic impurities are physically captured.Organic impurities having a boiling point of 250° C. or higher, which isrelatively high boiling point, are coarse in many cases (for example, acompound having 8 or more carbon atoms). Therefore, it is possible tocapture such organic impurities by using a filter having a pore diameterof about 1 nm.

For example, the structure of dioctyl phthalate is larger than 10 Å (=1nm). Therefore, in a case where an organic impurity-removing filterhaving a pore diameter of 1 nm is used, dioctyl phthalate cannot passthrough the pores of the filter. Accordingly, dioctyl phthalate isphysically captured by the filter and removed from the liquid to bepurified.

In this way, the organic impurity can be removed not only by a chemicalinteraction but also by a physical removing method. Here, in this case,a filter having a pore diameter of 3 nm or more is used as a “filtrationmember”, and a filter having a pore diameter less than 3 nm is used asan “organic impurity-removing filter”.

Examples of the filtering treatment using the metal ion adsorptionmember include filtering using a metal ion adsorption member comprisinga metal ion adsorption filter.

The metal ion adsorption member comprises at least one metal ionadsorption member. The metal ion adsorption member may have aconfiguration in which a plurality of metal ion adsorption filters isstacked depending on the intended purification level. In many cases, themetal ion adsorption member comprises the metal ion adsorption filterand a substrate on which the metal ion adsorption filter is fixed.

The metal ion adsorption filter comprises a function of adsorbing metalions in the liquid to be purified. In addition, the metal ion adsorptionfilter is preferably a filter capable of exchanging ions.

The metal ions to be adsorbed is not particularly limited, but arepreferably Fe, Cr, Ni, Pb, or Al because these are likely to causedefects in a semiconductor device.

From the viewpoint of improving the metal ion adsorption performance, itis preferable that the metal ion adsorption filter have an acid group onthe surface thereof. Examples of the acid group include a sulfo group, acarboxyl group, and the like.

Examples of the substrate (material) constituting the metal ionadsorption filter include cellulose, diatomite, nylon, polyethylene,polypropylene, polystyrene, a fluororesin, and the like.

The purification treatment performed in the purification step is notlimited to the aforementioned treatment. For example, a purificationtreatment may be performed which is selected from the group consistingof a distillation treatment using a distillation device, a filtrationtreatment for removing coarse particles, and a metal componentadsorption/purification treatment using silicon carbide described inWO2012/043496A.

In addition, as the purification step, each of the above treatments maybe performed alone, or a plurality of the above treatments may beperformed in combination. Furthermore, each of the treatments may beperformed once or multiple times.

In the present supply method, a commercially available high-purity gradeorganic solvent (particularly, an organic solvent having a low contentof organic impurities, metal components, and water) may also be used.

(Electricity Removing Treatment)

Before the chemical liquid is used in the present supply method, anelectricity removing treatment for reducing the charge potential of thechemical liquid may be performed on the chemical liquid.

The electricity removing treatment is not particularly limited, andknown electricity removing methods can be used. Examples thereof includea method of bringing the chemical liquid into contact with a conductivematerial.

The contact time for which the chemical liquid is brought into contactwith a conductive material is preferably 0.001 to 60 seconds, morepreferably 0.001 to 1 second, and even more preferably 0.01 to 0.1seconds. Examples of the conductive material include stainless steel,gold, platinum, diamond, and glassy carbon.

Examples of the method of bringing the chemical liquid into contact witha conductive material include a method of disposing a grounded meshconsisting of a conductive material in the interior of a pipe line andpassing the chemical liquid through the mesh.

It is preferable that the chemical liquid be prepared under an airtightcondition in an inert gas atmosphere where the water is highly unlikelyto be mixed into the chemical liquid. In order to suppress the mixing ofmoisture as much as possible, it is more preferable that the chemicalliquid be prepared in an inert gas atmosphere where a dewpoint is −70°C. or lower. This is because, in an inert gas atmosphere of −70° C. orlower, the water concentration in the gas phase is 2 ppm by mass orless, and thus water is unlikely to be mixed into the chemical liquid.

The chemical liquid may be temporarily stored in a container until thechemical liquid is used in the present supply method. As the containerfor storing the chemical liquid, known containers can be used withoutparticular limitation.

As the container storing the chemical liquid, a container formanufacturing semiconductor devices is preferable which has a highinternal cleanliness and hardly causes elution of impurities.

Examples of the usable container specifically include a “CLEAN BOTTLE”series manufactured by AICELLO CORPORATION and “PURE BOTTLE”manufactured by KODAMA PLASTICS Co., Ltd., but the container is notlimited to these.

It is preferable that the inside of the container be washed before thecontainer is filled with the chemical liquid. As the liquid used forwashing, the aforementioned chemical liquid or a liquid prepared bydiluting the chemical liquid is preferable. After being prepared, thechemical liquid may be bottled using a container, such as a gallonbottle or a quart bottle, and transported and/or stored. A glassmaterial or other materials may be used in the gallon bottle.

In order to prevent changes in the components of the chemical liquid,the inside of the container may be purged with an inert gas (such asnitrogen or argon) having a purity of 99.99995% by volume or higher.Particularly, a gas with a low moisture content is preferable. Althoughthe chemical liquid may be transported and stored at room temperature(25° C.), in order to prevent deterioration, the temperature may becontrolled in a range of −20° C. to 30° C.

[Gas Pumping Step]

The present supply method has a gas pumping step of sending the chemicalliquid by pressurization using a gas.

In the supply device 10 shown in FIG. 1 , a gas is introduced into thestorage tank 11 through the gas pipe 12, which increases the pressure ofthe gas accumulated in the head space in the upper portion of thestorage tank 11 and pressurizes a chemical liquid L stored in thestorage tank 11. The chemical liquid L is pressurized in this way, and apressure difference is made between the inside of the storage tank 11and the inside of the intermediate tank 14. As a result, the chemicalliquid L stored in the storage tank 11 is sent (pumped) to theintermediate tank 14 through the pipe line 13.

The position in the pipe line into which the pumping gas is introducedmay be a position other than the inside of the storage tank, as long asthe chemical liquid in the pipe line can be sent by pressurization ofthe chemical liquid. For example, the position may be inside of the pipelines 13 and 15.

The moisture content in the gas used in the gas pumping step of thepresent supply method (hereinafter, also called “pumping gas”) is0.00001 to 1 ppm by mass with respect to the total mass of the pumpinggas. Using a gas having a moisture content reduced to a specific rangeas described above makes it possible to reduce the content of impurities(particularly, an organic impurity) contained in the chemical liquidpumped by the gas pumping step.

Furthermore, setting the moisture content of the pumping gas to 0.00001%by mass or more makes it possible to reduce the content of impurities(particularly, an organic impurity) contained in the chemical liquidpumped by the gas pumping step. Details of the mechanism are unclear.According to the inventors of the present invention, presumably, becausethe electrostatic destruction of the liquid contact portion resultingfrom the accumulation of static electricity in the liquid contactportion of a member such as a pipe line can be suppressed, the contentof impurities could be reduced.

From the above viewpoint, the moisture content of the pumping gas withrespect to the total mass of the pumping gas is preferably 0.005 to 0.5ppm by mass, more preferably 0.01 to 0.3 ppm by mass, and even morepreferably 0.01 to 0.03 ppm by mass.

In addition, in view of further improving the effect of the presentinvention and making is possible to further reduce the content ofimpurities in the chemical liquid, the purity of the pumping gas ispreferably 99.9% by volume (3N) or more, and more preferably 99.999% byvolume (5N) or more.

The upper limit is not particularly limited, and may be equal to or morethan the detection limit.

The purity of the pumping gas means a volume ratio (percentage) of thecontent of a gas (total content in a case where two or more kinds ofgases are used), which is in a gas state in the atmosphere at 25° C. andhas a content of 99% by volume or more with respect to the total volumeof the pumping gas, to the content of components of the pumping gasexcept for water (water vapor).

That is, in the present specification, a component having a content lessthan 1% by volume with respect to the total volume of the pumping gascorresponds to an impurity gas.

Examples of the type of pumping gas include an inert gas such asnitrogen, argon, or helium, and dry air. In view of being capable offurther suppressing the elution of impurities from the pipe line, aninert gas is preferable, nitrogen or argon is more preferable, and argonis even more preferable.

As the pumping gas, one kind of the aforementioned gas may be usedalone, or two or more kinds of aforementioned gases may be used incombination.

The moisture content in the pumping gas, the purity of the pumping gas,and the type of pumping gas can be measured using an atmosphericpressure ionization mass spectrometer (API-MS) (for example,manufactured by NIPPON API CO., LTD.).

<Gas Purification Step>

The method of preparing the pumping gas, which is used in the presentsupply method and has a moisture content in the above range, is notparticularly limited. It is preferable to perform a gas purificationstep of removing water (water vapor) contained in a raw material gas toprepare the pumping gas.

Examples of more specific aspects of the gas purification step includean aspect in which a raw material gas is passed through the gas filter21 disposed on the gas pipe 12 in the supply device 10 shown in FIG. 1to prepare a pumping gas and the prepared pumping gas is introduced intothe storage tank 11.

Examples of the gas filter used in the gas purification step include anin-line gas filter such as “Wafergard (registered trademark) III NF-750”manufactured by Entegris Inc.

The raw material gas may be purified in advance to prepare the pumpinggas, before the pumping gas is supplied to the supply device. The methodof purifying the raw material gas in advance is not particularlylimited, and examples thereof include a method of treating the rawmaterial gas by using a known adsorbent such as molecular sieve,alumina, silica gel, or silica-alumina.

The supply pressure and flow rate of the gas in the gas pumping step arenot particularly limited, and may be appropriately set depending on theliquid feeding conditions and the pressure resistance of each membersuch as the storage tank, the gas pipe, and the control valve.

Regarding the gas supply pressure in the gas pumping step, the pressureof the gas pressurizing the chemical liquid is preferably 0.01 to 0.34MPa.

<Pump Transfer Step>

The supply device used in the present supply method may be provided witha section where a pump provided on the pipe line is used to transfer thechemical liquid in the pipe line. That is, the present supply method mayhave a pump transfer step of transferring the chemical liquid by using apump.

The section in the pipe line where the pump transfer step is performed(pump transfer section) may overlap with or be different from thesection in the pipe line where the gas pumping step is performed (gaspumping section).

In the case of the supply device 10 shown in FIG. 1 , the pipe line 13connecting the storage tank 11 to the intermediate tank 14 is the gaspumping section, and the pipe line 15 connecting the intermediate tank14 to a discharge port 16 is the pump transfer section.

In a case where the supply device in which the present supply method isimplemented is a treatment device that discharges the chemical liquidonto a wafer to perform various types of treatment, in the pipe linethat the supply device comprises, a section including a downstream endof the pipe line connecting a jetting portion having a function ofjetting the chemical liquid on a wafer is preferably the aforementionedpump transfer section. That is, it is preferable that the jetting of thechemical liquid from the supply device be performed using a pump.Performing the transfer of the chemical liquid by using a pump makes itpossible to accurately control the amount of the chemical liquid jettedto a wafer.

Examples of the type of pump used in the pump transfer step include anelectric submersible pump (electrical pump), a diaphragm pump, and acentrifugal pump (such as a magnetic pump).

In a case where a pump and a filter are provided on the pump transfersection, the position where the pump is provided is not particularlylimited. The pump may be provided on the upstream or downstream sidefrom the filter on the pipe line, and is preferably provided on theupstream side from the filter. In one pump transfer section, one pumpmay be used, or two or more pumps may be used in combination.

The supply pressure of the chemical liquid in the pump transfer step isnot particularly limited. The internal pressure of the pipe line on theupstream side of the filter is preferably 0.00010 to 1.0 MPa, and morepreferably 0.01 to 0.34 MPa.

The filtration pressure affects the filtration accuracy. Therefore, itis preferable that the pulsation of the supply pressure of the chemicalliquid applied to the filter be as low as possible. Examples of a methodof reducing the pulsation of the supply pressure of the chemical liquidinclude a method of using an adjusting valve and/or a damper disposed inthe pipe line on the upstream side of the filter.

<Purification Step>

Just as the supply device 10 shown in FIG. 1 comprises the filter unit20 on the pipe line 15, the supply device used in the present supplymethod may include a filter having a function of filtering and purifyingthe chemical liquid on the pipe line. That is, the present supply methodmay have a purification step of filtering the chemical liquid in thepipe line by using a filter.

It is preferable that the present supply method have the purificationstep, for the following reason. In the present supply method which is achemical liquid supply method having the aforementioned gas pumpingstep, in a case where the chemical liquid pumped using a pumping gashaving a specific moisture content is filtered by being passed through afilter, the impurity removing performance of the filter is improved, andthe impurity content in the purified chemical liquid can be furtherreduced.

Details of the mechanism through which the impurity removing performanceof the filter is improved are unclear. According to the inventors of thepresent invention, presumably, in a case where the gas pumping step isperformed using a gas having a moisture content reduced to a specificrange, the amount of moisture mixed into the chemical liquid from thegas may be reduced, and the elution of impurities into the chemicalliquid from the liquid contact portions of the pipe line and othermembers may be suppressed. As a result, static electricity is likely tobe accumulated in the filter, which may improve the impurity removingperformance of the filter. In contrast, in a case where the moisturecontent in the gas is set to be equal to or more than a predeterminedlower limit, a trace of moisture may be mixed into the chemical liquidfrom the gas, and the electrostatic destruction of the filter that leadsto the elution and/or mixing of impurities may be suppressed.

Particularly, it is more preferable that the present supply method havea purification step of filtering the chemical liquid sent by the gaspumping step by using a filter, because then the effect of improving theremoving performance of the filter is more markedly exhibited.

In the supply device 10, the purification step is performed as follows.

The chemical liquid stored in the intermediate tank 14 passes throughthe pipe line 15 by the pump 17 and is sent to the filter unit 20 havinga filter. The chemical liquid is filtered and purified while passingthrough the filter included in the filter cartridge housed in the filterunit 20. The purified chemical liquid flowing out of the filtercartridge 20 passes through the pipe line 15 and discharged from thedischarge port 16.

One filter or a plurality of filters may be used in the purificationstep. In a case where a plurality of filters is used, the filters may bearranged in series or arranged in a row in the chemical liquid transferdirection.

In addition, a circulation filtration may be performed in which thepurified chemical liquid that has passed through the filter may bereturned to the storage tank or the intermediate tank and repeatedlypassed through the filter. From the viewpoint of productivity and fromthe viewpoint of suppressing the mixing of impurities, the chemicalliquid may be passed through the filter only once without beingsubjected to circulation filtration.

(Filter)

Hereinafter, the filter used for purifying (filtering) the chemicalliquid in the purification step will be specifically described.

The pore diameter of the filter is not particularly limited, as long asthe pore diameter is generally used for filtering a chemical liquid. Thepore diameter of the filter is preferably 20 nm or less, more preferably5 nm or less, and even more preferably 2 nm or less. The lower limitthereof is not particularly limited, but is preferably 1 nm or more.

In a case where the supply device comprises a plurality of filters, itis preferable that the pore diameter of at least one filter is withinthe above range.

In the present specification, the pore diameter of a filter means a porediameter determined by the bubble point of isopropanol (IPA) or HFE-7200(“NOVEC 7200”, manufactured by 3M, hydrofluoroether, C₄F₉OC₂H₅).

The material constituting the filter is not particularly limited, andexamples thereof include a polyolefin (including a high densitypolyolefin and an ultra-high-molecular-weight polyolefin) such aspolyethylene (PE) or polypropylene (PP); a polyamide such as nylon(including nylon 6 and nylon 66); a polyimide; a polyamideimide; apolyester such as polyethylene terephthalate; polyether sulfone;cellulose; a fluorine resin such as polytetrafluoroethylene (PTFE) orperfluoroalkoxyalkane; and derivatives of the above polymers (orresins).

Among these, a material consisting of at least one polymer selected fromthe group consisting of a polyolefin, a polyamide, a polyimide, apolyamideimide, a polyester, a polysulfone, cellulose, a fluororesin,and derivatives of these is preferable. In view of being capable offurther reducing the impurity content in the chemical liquid,polyethylene, polypropylene, nylon, or a fluororesin is more preferable,and PTFE is even more preferable.

Examples of the material constituting the filter also include diatomiteand glass.

The material constituting the filter may be derivatives of theaforementioned polymers. Examples of the derivatives include aderivative obtained by introducing an ion exchange group into the abovepolymer by a chemical modification treatment.

Examples of the ion exchange group include a cation exchange group suchas a sulfonic acid group, a carboxy group, or a phosphoric acid group,and an anion exchange group such as a secondary, tertiary, or quaternaryammonium group. The method of introducing ion exchange groups into thepolymer is not particularly limited, and examples thereof include amethod of reacting a compound, which has ion exchange groups andpolymerizable groups, with the polymer such that a graft polymer ismade.

For example, in a case where a polyolefin (such as polyethylene orpolypropylene) is used, the polyolefin is irradiated with ionizingradiation (such as α-rays, β-rays, γ-rays, X-rays, an electron beams)such that an active moiety (radical) is generated in the molecular chainof the polyolefin. After being irradiated, the polyolefin is immersed ina monomer-containing solution such that the monomer isgraft-polymerized. As a result, a product is generated in which themonomer is bonded to the polyolefin as a side chain by graftpolymerization. By bringing the polyolefin fiber having the polymer as aside chain into contact with a compound having an anion exchange groupor a cation exchange group to cause a reaction between the polyolefinand the compound, an end product is obtained in which the ion exchangegroup is introduced into the monomer of the graft-polymerized sidechain. In such an end product, an ion exchange group is introduced notinto the polyolefin fiber which is the main chain, but into the monomerof the side chain graft-polymerized with the main chain.

Furthermore, the filter may be constituted with woven cloth or nonwovenfabric, in which ion exchange groups are formed by a radiation graftpolymerization method, combined with glass wool, woven cloth, ornonwoven fabric that is conventionally used.

Furthermore, the filter may have undergone a surface treatment otherthan chemical modification. As the surface treatment method, knownmethods can be used without particular limitation. Examples of thesurface treatment method include a plasma treatment, a hydrophobictreatment, coating, a gas treatment, and sintering.

The plasma treatment is preferable because the surface of the filter ismade hydrophilic by this treatment. Although the water contact angle onthe surface of each filter made hydrophilic by the plasma treatment isnot particularly limited, a static contact angle measured at 25° C. byusing a contact angle meter is preferably 60° or less, more preferably50° or less, and even more preferably 30° or less.

The pore structure of the filter is not particularly limited, and may beappropriately selected depending on the form of impurities contained inthe chemical liquid. The pore structure of the filter means a porediameter distribution, a positional distribution of pores in the filter,a pore shape, and the like, and varies with the manufacturing method ofthe filter.

For example, there is a difference in pore structure between a porousmembrane that is formed by sintering of powder of a resin or the likeand a fiber membrane that is formed by a method such as electrospinning,electroblowing, or melt blowing.

The critical surface tension of the filter is not particularly limited,and can be appropriately selected depending on the impurities to beremoved.

In the purification step, the temperature at which the chemical liquidis passed through the filter is preferably 0° C. to 50° C., and morepreferably 0° C. to 25° C.

In the purification step, the filtering speed of the chemical liquidpassing through the filter that is represented by a flow rate (L/min)per filtration area of the filter is preferably 0.6 L/min/m² or more,more preferably 0.75 L/min/m² or more, and even more preferably 1.0L/min/m² or more.

For the filter, an endurable differential pressure for assuring thefilter performance (assuring that the filter will not be broken) is set.In a case where the endurable differential pressure is high, byincreasing the filtering pressure, the filtering speed can be increased.The upper limit of the filtering speed depends on the endurabledifferential pressure of the filter, and is preferably 10.0 L/min/m² orless.

<Washing Step>

It is preferable that the supply device used in the present supplymethod be subjected to a washing step of cleaning the liquid contactportion of each member in the device before performing the presentsupply method. Washing each member (particularly, a filter) makes itpossible to further reduce the impurity content in the chemical liquidsupplied.

Examples of specific methods of the washing step include a method ofusing a washing solution instead of the chemical liquid and transferringthe washing solution in the pipe line according to the method describedin the above section of Gas pumping step or Pump transfer step.

Examples of the method of washing the filter include a method ofimmersing the filter in a washing solution, a method of causing awashing solution to flow through the filter, and a method of using thesemethods in combination.

The washing solution is not particularly limited, and an organic solventis preferable.

The organic solvent to be used as the washing solution is as describedabove as the organic solvent contained in the chemical liquid, includingpreferred aspects thereof.

The washing solution used in the washing step may be the same as ordifferent from the chemical liquid sent by the gas pumping step. Thewashing solution is preferably the same as the chemical liquid, becausethen a rinsing treatment using the chemical liquid is not required.

The method of transferring the washing solution in the washing step isnot particularly limited. It is possible to allow the washing solutionto flow in the pipe line or to pass the washing solution through thefilter, according to the method described above as the gas pumping stepand/or the pump transfer step.

In the washing step, there is no particular limit on the supply pressureof the washing solution in a case where the washing solution is passedthrough the filter. For example, the internal pressure of the pipe lineon the upstream side from the filter may be 0.0001 to 1.0 MPa.

The flow rate of the washing solution passed through the filter in thewashing step is preferably 0.6 to 10.0 L/min/m² in terms of a flow rate(L/min) per filtration area of the filter.

The temperature of the washing solution used in the washing step ispreferably 0° C. to 50° C.

The washing step may be performed only once or performed twice or more.

It is preferable that all of the present supply method, the purificationof the chemical liquid, and other additional steps, such as opening of acontainer, washing of a container and a device, storage of a solution,and analysis, be performed in a clean room. It is preferable that theclean room meet the clean room standard described in internationalorganization for standardization (ISO) 14644-1. The clean room morepreferably meets any of International Organization for Standardization(ISO) class 1, ISO class 2, ISO class 3, or ISO class 4, even morepreferably meets ISO class 1 or ISO class 2, and particularly preferablymeets ISO class 1.

[Use of Chemical Liquid]

The chemical liquid supplied by the present supply method is preferablyused for manufacturing a semiconductor device. The chemical liquid canbe used in any step for manufacturing a semiconductor device. Forexample, the chemical liquid can be used for a treatment using anorganic substance in a wiring line forming process includingphotolithography (including a lithography step, an etching step, an ionimplantation step, a peeling step, and the like). Examples of specificuses of the chemical liquid include a pre-wet liquid, a developer, arinsing liquid, a stripper, a CMP slurry, and a post-CMP rinsing liquid(p-CMP rinsing liquid).

The chemical liquid may be used after being diluted with another organicsolvent and/or a solvent such as water. In a case where the chemicalliquid is used as a CMP slurry, for example, additives such as abrasivegrains and an oxidant may be added to the chemical liquid. Furthermore,the chemical liquid can also be used as a solvent for diluting the CMPslurry.

The chemical liquid may be used for only one of the aforementioned uses,or may be used for two or more uses among the above.

[Pattern Forming Method]

It is preferable that the chemical liquid supplied by the present supplymethod be used as a treatment liquid in a pattern forming method havingthe following steps.

(A) A pre-wetting step of bringing a pre-wet liquid into contact withthe surface of a substrate,

(B) a resist film forming step of forming a resist film on the substratehaving undergone the pre-wetting step by using a resist composition,

(C) an exposure step of exposing the resist film,

(D) a development step of developing the exposed resist film by using adeveloper, and

(E) a rinsing step of bringing a rinsing liquid into contact with thesubstrate on which the resist pattern is formed.

A pattern forming method is more preferable which has the above steps(A) to (E) and uses the aforementioned chemical liquid as at least oneliquid selected from the group consisting of the pre-wet liquid,developer, and rinsing liquid described above.

Hereinafter, each step included in the pattern forming method will bedescribed.

<(A) Pre-Wetting Step>

The pre-wetting step is a step of bringing a pre-wet liquid into contactwith the surface of a substrate.

As the substrate, known substrates used for manufacturing semiconductorscan be used without particular limitation. Examples of the substrateinclude an inorganic substrate such as silicon, SiO₂, or SiN, acoating-type inorganic substrate such as Spin On Glass (SOG), and thelike.

Furthermore, the substrate may be a substrate with an antireflectionfilm comprising an antireflection film. As the antireflection film, aknown organic or inorganic antireflection film can be used.

The method of bringing the pre-wet liquid into contact with the surfaceof a substrate is not particularly limited, and a known coating methodcan be used. Particularly, as the coating method, spin coating ispreferable because this method makes it possible to form a uniformresist film by using smaller amounts of resist composition in the resistfilm forming step which will be described later.

The thickness of a pre-wet liquid layer formed on the substrate by usingthe pre-wet liquid is preferably 0.001 to 10 μm, and more preferably0.005 to 5 μm.

(Pre-Wet Liquid)

As the pre-wet liquid, a pre-wet liquid containing an organic solvent ispreferable. As the organic solvent contained in the pre-wet liquid, forexample, at least one kind of organic solvent is preferable which isselected from the group consisting of a hydrocarbon-based solvent, aketone-based solvent, an ester-based solvent, an alcohol-based solvent,an amide-based solvent, and an ether-based solvent, a hydrocarbon-basedsolvent, an ether-based solvent, or a ketone-based solvent is morepreferable, and a hydrocarbon-based solvent or an ether-based solvent iseven more preferable.

The chemical liquid supplied by the present supply method can be used asthe aforementioned pre-wet liquid.

It is preferable that the surface tension of the pre-wet liquid behigher than the surface tension of the resist composition to be used forcoating.

Generally, the pre-wet liquid is supplied to the wafer by a method ofmoving a prewet nozzle to a position above the central portion of thewafer. Then, by opening or closing a valve, the pre-wet liquid issupplied to the wafer.

In a state where the wafer stands still, a predetermined amount of thepre-wet liquid is supplied to the central portion of the wafer from theprewet nozzle. Then, the wafer is rotated at a first velocity V1 of, forexample, about 500 rotations per minute (rpm) such that the pre-wetliquid on the wafer is diffused over the entire surface of the wafer,which makes the entire surface of the wafer wet with the pre-wet liquid.

The upper limit of the first velocity V1 is not particularly limited,but is preferably 3,000 rpm or less.

Thereafter, the valve of a line connected to a resist composition isopened. As a result, the resist composition starts to be jetted from aresist nozzle, and the resist composition starts to be supplied to thecentral portion of the wafer.

The resist composition may be a resist composition for ArF exposure, aresist composition for EUV exposure, or a resist composition for KrFexposure. That is, the pre-wet liquid may be a pre-wet liquid that isused by being applied to a substrate to be coated with a resistcomposition for ArF exposure is applied, a pre-wet liquid that is usedby being applied to a substrate to be coated with a resist compositionfor EUV exposure, or a pre-wet liquid that is used by being applied to asubstrate to be coated with a resist composition for KrF exposure.

In this way, (B) resist film forming step (described later) is started.In the resist film forming step, from the first velocity V1, therotation speed of the wafer is increased to a second velocity V2 ofabout 2,000 to 4,000 rpm, for example. The wafer rotating at the firstvelocity V1 before the start of the resist film forming step is thengradually accelerated such that the speed continuously and smoothlychanges. At this time, the acceleration of the rotation of the wafer isgradually increased from zero, for example. In order to finish theresist film forming step, the acceleration of the rotation of the waferis reduced such that the rotation speed of the wafer smoothly reachesthe second velocity V2. In this way, during the resist film formingstep, the rotation speed of the wafer changes such that the transitionfrom the first velocity V1 to the second velocity V2 is represented byan S-shaped curve. In the resist film forming step, due to thecentrifugal force, the resist composition supplied to the centralportion of the wafer spreads over the entire surface of the wafer,whereby the surface of the wafer is coated with the resist composition.

The technique for saving resist by changing the rotation speed of awafer at the time of resist coating is specifically described inJP2009-279476A.

The interval between a point in time when (A) pre-wetting step hasfinished and a point in time when resist composition coating in (B)resist film forming step is started is not particularly limited, but ispreferably 7 seconds or less.

The pre-wet liquid may be recycled. That is, the pre-wet liquid used inthe pre-wetting step can be recovered and used in the pre-wetting stepfor other wafers.

In a case where the pre-wet liquid is recycled, it is preferable toadjust the content of the impurity metal, organic impurity, water, andthe like contained in the recovered pre-wet liquid. The adjustmentmethod is as described above as the manufacturing method of the pre-wetliquid.

<(B) Resist Film Forming Step>

The resist film forming step is a step of forming a resist film on thesubstrate having undergone the pre-wetting step by using a resistcomposition (preferably, by coating the substrate with a resistcomposition).

The substrate having undergone the pre-wetting step is a substratecomprising a pre-wet liquid layer, and is also called a pre-wettedsubstrate.

Hereinafter, first, the form of the resist composition will bedescribed.

<Resist Composition>

The resist composition that can be used in the resist film forming stepis not particularly limited, and a known resist composition can be used.

The resist composition may be, for example, for positive tonedevelopment or negative tone development. The light for exposure of theresist film formed of the resist composition is not limited. Forexample, the resist composition may be a resist composition for ArFexposure, a resist composition for EUV exposure, or a resist compositionfor KrF exposure.

It is preferable that the resist composition contain a resin whichcontains a repeating unit containing a group generating a polar group(such as a carboxyl group or a phenolic hydroxyl group) by beingdecomposed by the action of an acid (hereinafter, the resin will be alsocalled “acid-decomposable resin” in the present specification) and acompound which generates an acid by the irradiation with actinic rays orradiation (hereinafter, the compound will be also called “photoacidgenerator” in the present specification).

Particularly, the following resist compositions are preferable.

-   -   Resist composition containing resin represented by Formula (I)        which will be described later    -   Resist composition containing acid-decomposable resin having        phenolic hydroxyl group which will be described later    -   Resist composition containing hydrophobic resin, which will be        described later, and acid-decomposable resin

Hereinafter, each of the components of the resist compositions will bedescribed.

(Acid-Decomposable Resin)

In the acid-decomposable group, the polar group is protected with agroup dissociated by an acid (acid-dissociable group). Examples of theacid-dissociable group include —C(R₃₆)(R₃₇)(R₃₈), —C(R₃₆)(R₃₇)(OR₃₉),—C(R₀₁)(R₀₂)(OR₃₉), and the like.

In the Formulas, R₃₆ to R₃₉ each independently represent an alkyl group,a cycloalkyl group, an aryl group, an aralkyl group, or an alkenylgroup. R₃₆ and R₃₇ may be bonded to each other to form a ring.

R₀₁ and R₀₂ each independently represent a hydrogen atom, an alkylgroup, a cycloalkyl group, an aryl group, an aralkyl group, or analkenyl group.

Examples of the acid-decomposable resin include a resin P having anacid-decomposable group represented by Formula (AI).

In Formula (AI),

Xa₁ represents a hydrogen atom or an alkyl group which may have asubstituent.

represents a single bond or a divalent linking group.

Ra₁ to Ra₃ each independently represent an alkyl group (linear orbranched) or a cycloalkyl group (monocyclic or polycyclic).

Two out of Ra₁ to Ra₃ may be bonded to each other to form a cycloalkylgroup (monocyclic or polycyclic).

Examples of the alkyl group which is represented by Xa₁ and may have asubstituent include a methyl group and a group represented by —CH₂—R₁₁.R₁₁ represents a halogen atom (such as a fluorine atom), a hydroxylgroup, or a monovalent organic group.

Xa₁ is preferably a hydrogen atom, a methyl group, a trifluoromethylgroup, or a hydroxymethyl group.

Examples of the divalent linking group represented by T include analkylene group, a —COO-Rt- group, a —O—Rt- group, and the like. In theFormulas, Rt represents an alkylene group or a cycloalkylene group.

T is preferably a single bond or a —COO—Rt- group. Rt is preferably analkylene group having 1 to 5 carbon atoms, and more preferably a —CH₂—group, a —(CH₂)₂— group, or a —(CH₂)₃— group.

The alkyl group represented by R_(a1) to R_(a3) preferably has 1 to 4carbon atoms.

The cycloalkyl group represented by Ra₁ to Ra₃ is preferably amonocyclic cycloalkyl group such as a cyclopentyl group or a cyclohexylgroup or a polycyclic cycloalkyl group such as a norbornyl group, atetracyclodecanyl group, a tetracyclododecanyl group, or an adamantylgroup.

The cycloalkyl group formed by the bonding of two groups out of Ra₁ toRa₃ is preferably a monocyclic cycloalkyl group such as a cyclopentylgroup or a cyclohexyl group or a polycyclic cycloalkyl group such as anorbornyl group, a tetracyclodecanyl group, a tetracyclododecanyl group,or an adamantyl group. The cycloalkyl group is more preferably amonocyclic cycloalkyl group having 5 or 6 carbon atoms.

In the cycloalkyl group formed by the bonding of two groups out of Ra₁to Ra₃, for example, one methylene group constituting the ring may besubstituted with a heteroatom such as an oxygen atom or a group having aheteroatom such as a carbonyl group.

As the repeating unit represented by Formula (AI), for example, anaspect is preferable in which Ra₁ is a methyl group or an ethyl group,and Ra₂ and Ra₃ are bonded to each other to form the aforementionedcycloalkyl group.

Each of the above groups may have a substituent. Examples of thesubstituent include an alkyl group (having 1 to 4 carbon atoms), ahalogen atom, a hydroxyl group, an alkoxy group (having 1 to 4 carbonatoms), a carboxy group, an alkoxycarbonyl group (having 2 to 6 carbonatoms), and the like. The number of carbon atoms in the substituent ispreferably equal to or smaller than 8.

The total content of the repeating unit represented by Formula (AI) withrespect to all the repeating units in the resin P is preferably 20 to 90mol %, more preferably 25 to 85 mol %, and even more preferably 30 to 80mol %.

Specific examples of the repeating unit represented by Formula (AI) willbe shown below, but the present invention is not limited thereto.

In the specific examples, Rx and Xa₁ each independently represent ahydrogen atom, CH₃, CF₃, or CH₂OH. Rxa and Rxb each represent an alkylgroup having 1 to 4 carbon atoms. Z represents a substituent containinga polar group. In a case where there is a plurality of Z's, Z's areindependent from each other. p represents 0 or a positive integer.Examples of the substituent represented by Z containing a polar groupinclude a hydroxyl group, a cyano group, an amino group, an alkylamidegroup, a sulfonamide group, and a linear or branched alkyl group orcycloalkyl group having these groups.

(Repeating Unit Having Lactone Structure)

It is preferable that the resin P contain a repeating unit Q having alactone structure.

The repeating unit Q having a lactone structure preferably has a lactonestructure on a side chain. For example, the repeating unit Q is morepreferably a repeating unit derived from a (meth)acrylic acid derivativemonomer.

One kind of repeating unit Q having a lactone structure may be usedsingly, or two or more kinds of repeating units Q may be used incombination. It is preferable to use one kind of repeating unit Q.

The content of the repeating unit Q having a lactone structure withrespect to all the repeating units in the resin P is, for example, 3 to80 mol %, and preferably 3 to 60 mol %.

The lactone structure is preferably a 5- to 7-membered lactonestructure, and more preferably a structure in which another ringstructure is fused with a 5- to 7-membered lactone structure by forminga bicyclo structure or a spiro structure.

It is preferable that the lactone structure have a repeating unit havinga lactone structure represented by any of Formulas (LC1-1) to (LC1-17).As the lactone structure, a lactone structure represented by Formula(LC1-1), Formula (LC1-4), Formula (LC1-5), or Formula (LC1-8) is morepreferable, and a lactone structure represented by Formula (LC1-4) iseven more preferable.

The lactone structure portion may have a substituent (Rb₂). As thesubstituent (Rb₂), for example, an alkyl group having 1 to 8 carbonatoms, a cycloalkyl group having 4 to 7 carbon atoms, an alkoxy grouphaving 1 to 8 carbon atoms, an alkoxycarbonyl group having 2 to 8 carbonatoms, a carboxyl group, a halogen atom, a hydroxyl group, a cyanogroup, an acid-decomposable group, and the like are preferable. n₂represents an integer of 0 to 4. In a case where n₂ 2 or more, aplurality of substituents (Rb₂) may be the same as or different fromeach other, and a plurality of substituents (Rb₂) may be bonded to eachother to form a ring.

The resin P is preferably a resin including a repeating unit selectedfrom the group consisting of a repeating unit represented by Formula(a), a repeating unit represented by Formula (b), a repeating unitrepresented by Formula (c), a repeating unit represented by Formula (d),and a repeating unit represented by Formula (e) (hereinafter, this resinwill be referred to as “resin represented by Formula (I)” as well).

The resin represented by Formula (I) is a resin whose solubility in adeveloper, which contains an organic solvent as a main component, isreduced by the action of an acid. The resin contains anacid-decomposable group. In the pre-wet liquid, the resin represented byFormula (I) is excellently dissolved. Therefore, the pre-wet liquidmakes it easy to obtain a uniform resist film by using smaller amountsof the resist composition. Hereinafter, the resin represented by Formula(I) will be described.

The resin represented by the Formula (I) may be a resin thatsubstantially consists of only the repeating units represented byFormulas (a) to (e). For example, in the resin represented by Formula(I), the content of repeating units other than the repeating unitsrepresented by Formulas (a) to (e) may be in a range of 0 to 5 mol %(more preferably in a range of 0 to 1 mol %) with respect to all therepeating units of the resin.

Resin Represented by Formula (I)

Formula (I) is constituted with a repeating unit (a) (repeating unitrepresented by Formula (a)), a repeating unit (b) (repeating unitrepresented by Formula (b)), a repeating unit (c) (repeating unitrepresented by Formula (c)), a repeating unit (d) (repeating unitrepresented by Formula (d)), and a repeating unit (e) (repeating unitrepresented by Formula (e)).

R_(x1) to R_(x5) each independently represent a hydrogen atom or analkyl group which may have a substituent.

R₁ to R₄ each independently represent a monovalent substituent, and p₁to p₄ each independently represent 0 or a positive integer.

R_(a) represents a linear or branched alkyl group.

T₁ to T₅ each independently represent a single bond or a divalentlinking group.

R₅ represents a monovalent organic group.

a to e each represent mol % (mol % of each repeating unit with respectto a total of 100 mol % of the repeating units (a) to (e)). a to e eachindependently represent a number included in ranges of 0≤a≤100, 0≤b≤100,0≤c≤100, 0≤d≤100, and 0≤e≤100. Here, a+b+c+d+e=100, and a+b≠0.

In Formula (I), the repeating unit (e) has a structure different fromall of the repeating units (a) to (d).

Examples of the alkyl group represented by R_(x1) to R_(x5) that maycontain a substituent include a methyl group and a group represented by—CH₂—R₁₁. R₁₁ represents a halogen atom (such as a fluorine atom), ahydroxyl group, or a monovalent organic group.

R_(x1) to R_(x5) preferably each independently represent a hydrogenatom, a methyl group, a trifluoromethyl group, or a hydroxymethyl group.

Examples of the divalent linking group represented by T₁ to T₅ inFormula (I) include an alkylene group, a —COO—Rt- group, a —O—Rt- group,and the like. In the Formulas, Rt represents an alkylene group or acycloalkylene group.

T₁ to T₅ preferably each independently represent a single bond or a—COO—Rt- group. Rt is preferably an alkylene group having 1 to 5 carbonatoms, and more preferably a —CH₂— group, a —(CH₂)₂— group, or a—(CH₂)₃— group.

In Formula (I), R_(a) represents a linear or branched alkyl group.Examples thereof include a methyl group, an ethyl group, a t-butylgroup, and the like. Among these, a linear or branched alkyl grouphaving 1 to 4 carbon atoms is preferable.

In Formula (I), R₁ to R₄ each independently represent a monovalentsubstituent. R₁ to R₄ are not particularly limited, and examples thereofinclude a hydroxyl group, a cyano group, and a linear or branched alkylor cycloalkyl group having a hydroxyl group, a cyano group, and thelike.

In Formula (I), p₁ to p₄ each independently represent 0 or a positiveinteger. The upper limit of p₁ to p₄ equals the number of hydrogen atomswhich can be substituted in each repeating unit.

In formula (I), R₅ represents a monovalent organic group. R₅ is notparticularly limited, and examples thereof include a monovalent organicgroup having a sultone structure, a monovalent organic group having acyclic ether such as tetrahydrofuran, dioxane, 1,4-thioxane, dioxolane,and 2,4,6-trioxabicyclo[3.3.0]octane, and an acid-decomposable group(for example, an adamantyl group quaternized by the substitution ofcarbon at a position bonded to a —COO group with an alkyl group).

The repeating unit (b) in Formula (I) is preferably formed of themonomer described in paragraphs “0014” to “0018” of JP2016-138219A.

In Formula (I), a to e each represent mol % (mol % of each repeatingunit with respect to a total of 100 mol % of the repeating units (a) to(e)). a to e each independently represent a number included in ranges of0≤a≤100, 0≤b≤100, 0≤c<100, 0≤d<100, and 0≤e<100. Here, a+b+c+d+e=100,and a+b≠0.

In Formula (I), a+b is preferably 20 to 90 mol %, more preferably 25 to85 mol %, and even more preferably 30 to 80 mol %.

In Formula (I), the content of the repeating unit having anacid-decomposable group with respect to all the repeating units ispreferably 20 to 90 mol %, more preferably 25 to 85 mol %, and even morepreferably 30 to 80 mol %.

Furthermore, in Formula (I), c+d (the content of the repeating unithaving a lactone structure with respect to all the repeating units) ispreferably 3 to 80 mol %, and more preferably 3 to 60 mol %.

One kind of each of the repeating unit (a) to repeating unit (e) may beused singly, or two or more kinds of each of the repeating unit (a) torepeating unit (e) may be used in combination. In a case where two ormore kinds of repeating units are used in combination, the total contentof each repeating unit is preferably within the above range.

The weight-average molecular weight (Mw) of the resin represented byFormula (I) is preferably 1,000 to 200,000 in general, more preferably2,000 to 20,000, and even more preferably 3,000 to 15,000. Theweight-average molecular weight is determined by Gel PermeationChromatography (GPC) by using tetrahydrofuran (THF) as a developingsolvent, and expressed in terms of polystyrene.

In the resist composition, the content of the resin represented byFormula (I) based on the total solid content of the resist compositionis preferably 30% to 99% by mass in general, and more preferably 50% to95% by mass.

(Repeating Unit Having Phenolic Hydroxyl Group)

The resin P may contain a repeating unit having a phenolic hydroxylgroup.

Examples of the repeating unit having a phenolic hydroxyl group includea repeating unit represented by General Formula (I).

In the formula, R₄₁, R₄₂, and R₄₃ each independently represent ahydrogen atom, an alkyl group, a halogen atom, a cyano group, or analkoxycarbonyl group. Here, R₄₂ and Ar₄ may be bonded to each other toform a ring. In this case, R₄₂ represents a single bond or an alkylenegroup.

X₄ represents a single bond, —COO—, or —CONR₆₄—, and R₆₄ represents ahydrogen atom or an alkyl group.

L₄ represents a single bond or an alkylene group.

Ar₄ represents an (n+1)-valent aromatic ring group. In a case where Ar₄forms a ring by being bonded to R₄₂, Ar₄ represents an (n+2)-valentaromatic ring group.

n represents an integer of 1 to 5.

The alkyl group represented by R₄₁, R₄₂, and R₄₃ in General Formula (I)is preferably an alkyl group having 20 or less carbon atoms such as amethyl group, an ethyl group, a propyl group, an isopropyl group, an-butyl group, a sec-butyl group, a hexyl group, a 2-ethylhexyl group,an octyl group, or a dodecyl group which may have a substituent, morepreferably an alkyl group having 8 or less carbon atoms, and even morepreferably an alkyl group having 3 or less carbon atoms.

The cycloalkyl group represented by R₄₁, R₄₂, and R₄₃ in General Formula(I) may be monocyclic or polycyclic. The cycloalkyl group is preferablya monocyclic cycloalkyl group having 3 to 8 carbon atoms such as acyclopropyl group, a cyclopentyl group, or a cyclohexyl group which mayhave a substituent.

Examples of the halogen atom represented by R₄₁, R₄₂, and R₄₃ in GeneralFormula (I) include a fluorine atom, a chlorine atom, a bromine atom,and an iodine atom. Among these, a fluorine atom is preferable.

As the alkyl group contained in the alkoxycarbonyl group represented byR₄₁, R₄₂, and R₄₃ in General Formula (I), the same alkyl group as thealkyl group represented by R₄₁, R₄₂, and R₄₃ described above ispreferable.

Examples of the substituent in each of the above groups include an alkylgroup, a cycloalkyl group, an aryl group, an amino group, an amidegroup, a ureide group, a urethane group, a hydroxyl group, a carboxylgroup, a halogen atom, an alkoxy group, a thioether group, an acylgroup, an acyloxy group, an alkoxycarbonyl group, a cyano group, a nitrogroup, and the like. The number of carbon atoms in the substituent ispreferably equal to or smaller than 8.

Ar₄ represents an (n+1)-valent aromatic ring group. Examples of adivalent aromatic ring group obtained in a case where n is 1 include anarylene group having 6 to 18 carbon atoms such as a phenylene group, atolylene group, a naphthylene group, or an anthracenylene group whichmay have a substituent and an aromatic ring group containing a heteroring such as thiophene, furan, pyrrole, benzothiophene, benzofuran,benzopyrrole, triazine, imidazole, benzimidazole, triazole, thiadiazole,or thiazole.

Specific examples of the (n+1)-valent aromatic ring group obtained in acase where n is an integer equal to or greater than 2 include groupsobtained by removing (n−1) pieces of any hydrogen atoms from thespecific examples of the divalent aromatic ring group described above.

The (n+1)-valent aromatic ring group may further have a substituent.

Examples of the substituent that the alkyl group, the cycloalkyl group,the alkoxycarbonyl group, the alkylene group, and the (n+1)-valentaromatic ring group described above can include the alkyl groupexemplified as R₄₁, R₄₂, and R₄₃ in General Formula (I); an alkoxy groupsuch as a methoxy group, an ethoxy group, a hydroxyethoxy group, apropoxy group, a hydroxypropoxy group, or a butoxy group; and an arylgroup such as a phenyl group.

Examples of the alkyl group represented by R₆₄ in —CONR₆₄— (R₆₄represents a hydrogen atom or an alkyl group) represented by X₄ includean alkyl group having 20 or less carbon atoms such as a methyl group, anethyl group, a propyl group, an isopropyl group, a n-butyl group, asec-butyl group, a hexyl group, a 2-ethylhexyl group, an octyl group, ora dodecyl group which may have a substituent. Among these, an alkylgroup having 8 or less carbon atoms is preferable.

X₄ is preferably a single bond, —COO—, or —CONH—, and more preferably asingle bond or —COO—.

The alkylene group represented by L₄ is preferably an alkylene grouphaving 1 to 8 carbon atoms such as a methylene group, an ethylene group,a propylene group, a butylene group, a hexylene group, or an octylenegroup which may have a substituent.

Ar₄ is preferably an aromatic ring group having 6 to 18 carbon atomsthat may have a substituent, and more preferably a benzene ring group, anaphthalene ring group, or a biphenylene ring group.

It is preferable that the repeating unit represented by General Formula(I) comprise a hydroxystyrene structure. That is, Ar₄ is preferably abenzene ring group.

The repeating unit having a phenolic hydroxyl group is preferably arepeating unit represented by General Formula (p1).

R in General Formula (p1) represents a hydrogen atom, a halogen atom, ora linear or branched alkyl group having 1 to 4 carbon atoms. A pluralityof R's may be the same as or different from each other. As R in GeneralFormula (p1), a hydrogen atom is preferable.

Ar in General Formula (p1) represents an aromatic ring, and examplesthereof include an aromatic hydrocarbon ring having 6 to 18 carbon atomsthat may have a substituent, such as a benzene ring, a naphthalene ring,an anthracene ring, a fluorene ring, or a phenanthrene ring, and anaromatic hetero ring containing a hetero ring such as a thiophene ring,a furan ring, a pyrrole ring, a benzothiophene ring, a benzofuran ring,a benzopyrrole ring, a triazine ring, an imidazole ring, a benzimidazolering, a triazole ring, a thiadiazole ring, or a thiazole ring. Amongthese, a benzene ring is preferable.

m in General Formula (p1) represents an integer of 1 to 5. m ispreferably 1.

Specific examples of the repeating unit having a phenolic hydroxyl groupwill be shown below, but the repeating unit is not limited thereto. Inthe formulas, a represents 1 or 2.

The content of the repeating unit having a phenolic hydroxyl group withrespect to all the repeating units in the resin P is preferably 0 to 50mol %, more preferably 0 to 45 mol %, and even more preferably 0 to 40mol %.

(Repeating Unit Containing Organic Group Having Polar Group)

The resin P may further contain a repeating unit containing an organicgroup having a polar group, particularly, a repeating unit having analicyclic hydrocarbon structure substituted with a polar group.

In a case where the resin (A) has such a repeating unit, the substrateadhesiveness and the affinity for a developer are improved. As thealicyclic hydrocarbon structure substituted with a polar group, anadamantyl group, a diamantyl group, or a norbornane group is preferable.As the polar group, a hydroxyl group or a cyano group is preferable.

Specific examples of the repeating unit having a polar group will beshown below, but the repeating unit is not limited thereto.

In a case where the resin P contains the repeating unit containing anorganic group having a polar group, the content of the repeating unitwith respect to all the repeating units in the resin P is preferably 1to 50 mol %, more preferably 1 to 30 mol %, even more preferably 5 to 25mol %, and particularly preferably 5 to 20 mol %.

(Repeating unit having group (photoacid generating group) generatingacid by irradiation of actinic rays or radiation)

The resin P may contain a repeating unit having a group (photoacidgenerating group) generating an acid by the irradiation of actinic raysor radiation.

Examples of the repeating unit having a group (photoacid generatinggroup) generating an acid by the irradiation of actinic rays orradiation include a repeating unit represented by Formula (4).

R⁴¹ represents a hydrogen atom or a methyl group. L⁴¹ represents asingle bond or a divalent linking group. L⁴² represents a divalentlinking group. W represents a structural moiety generating an acid on aside chain by being decomposed by the irradiation with actinic rays orradiation.

Specific examples of the repeating unit represented by Formula (4) willbe shown below, but the present repeating unit is not limited thereto.

Examples of the repeating unit represented by Formula (4) also includethe repeating units described in paragraphs “0094” to “0105” ofJP2014-041327A.

In a case where the resin P contains the repeating unit having aphotoacid generating group, the content of the repeating unit having aphotoacid generating group with respect to all the repeating units inthe resin P is preferably 1 to 40 mol %, more preferably 5 to 35 mol %,and even more preferably 5 to 30 mol %.

The resin P may contain a repeating unit represented by Formula (VI).

In Formula (VI), R₆₁, R₆₂, and R₆₃ each independently represent ahydrogen atom, an alkyl group, a cycloalkyl group, a halogen atom, acyano group, or an alkoxycarbonyl group. Here, R₆₂ may be bonded to Ar₆to form a ring, and in this case, R₆₂ represents a single bond or analkylene group.

X₆ represents a single bond, —COO—, or —CONR₆₄—. R₆₄ represents ahydrogen atom or an alkyl group.

L₆ represents a single bond or an alkylene group.

Ar₆ represents an (n+1)-valent aromatic ring group. In a case where Ar₆forms a ring by being bonded to R₆₂, Ar₆ represents an (n+2)-valentaromatic ring group.

In a case where n≥2, Y₂ each independently represent a hydrogen atom ora group which is dissociated by the action of an acid. Here, at leastone of Y₂'s represents a group which is dissociated by the action of anacid.

n represents an integer of 1 to 4.

As the group Y₂ which is dissociated by the action of an acid, astructure represented by Formula (VI-A) is preferable.

L₁ and L₂ each independently represent a hydrogen atom, an alkyl group,a cycloalkyl group, an aryl group, or a group obtained by combining analkylene group and an aryl group.

M represents a single bond or a divalent linking group.

Q represents an alkyl group, a cycloalkyl group which may contain aheteroatom, an aryl group which may contain a heteroatom, an aminogroup, an ammonium group, a mercapto group, a cyano group, or analdehyde group.

At least two out of Q, M, and Li may form a ring (preferably a 5- or6-membered ring) by being bonded to each other.

The repeating unit represented by Formula (VI) is preferably a repeatingunit represented by Formula (3).

In Formula (3), Ar₃ represents an aromatic ring group.

R₃ represents a hydrogen atom, an alkyl group, a cycloalkyl group, anaryl group, an aralkyl group, an alkoxy group, an acyl group, or aheterocyclic group.

M₃ represents a single bond or a divalent linking group.

Q₃ represents an alkyl group, a cycloalkyl group, an aryl group, or aheterocyclic group.

At least two out of Q₃, M₃, and R₃ may form a ring by being bonded toeach other.

The aromatic ring group represented by Ar₃ is the same as Ar₆ in Formula(VI) in a case where n in Formula (VI) is 1. Ar₃ is more preferably aphenylene group or a naphthylene group, and even more preferably aphenylene group.

Specific examples of the repeating unit represented by Formula (VI) willbe shown below, but the repeating unit is not limited thereto.

The resin P may contain a repeating unit represented by Formula (4).

In Formula (4), R₄₁, R₄₂, and R₄₃ each independently represent ahydrogen atom, an alkyl group, a cycloalkyl group, a halogen atom, acyano group, or an alkoxycarbonyl group. R₄₂ and L₄ may be bonded toeach other to form a ring, and in this case, R₄₂ represents an alkylenegroup.

L₄ represents a single bond or a divalent linking group. In a case whereL₄ forms a ring together with R₄₂, L₄ represents a trivalent linkinggroup.

R₄₄ and R₄₅ each represent a hydrogen atom, an alkyl group, a cycloalkylgroup, an aryl group, an aralkyl group, an alkoxy group, an acyl group,or a heterocyclic group.

M₄ represents a single bond or a divalent linking group.

Q₄ represents an alkyl group, a cycloalkyl group, an aryl group, or aheterocyclic group.

At least two out of Q₄, M₄, and R₄₄ may form a ring by being bonded toeach other.

R₄₁, R₄₂, and R₄₃ have the same definition as R₄₁, R₄₂, and R₄₃ inFormula (IA), and the preferable range thereof is also the same.

L₄ has the same definition as T in Formula (AI), and the preferablerange thereof is also the same.

R₄₄ and R₄₅ have the same definition as R₃ in Formula (3), and thepreferable range thereof is also the same.

M₄ has the same definition as M₃ in Formula (3), and the preferablerange thereof is also the same.

Q₄ has the same definition as Q₃ in Formula (3), and the preferablerange thereof is also the same.

Examples of the ring formed by the bonding of at least two out of Q₄,M₄, and R₄₄ include a ring formed by the bonding of at least two out ofQ₃, M₃, and R₃, and the preferable range thereof is also the same.

Specific examples of the repeating unit represented by Formula (4) willbe shown below, but the repeating unit is not limited thereto.

The resin P may contain a repeating unit represented by Formula (BZ).

In Formula (BZ), AR represents an aryl group. Rn represents an alkylgroup, a cycloalkyl group, or an aryl group. Rn and AR may be bonded toeach other to form a nonaromatic ring.

R₁ represents a hydrogen atom, an alkyl group, a cycloalkyl group, ahalogen atom, a cyano group, or an alkyloxycarbonyl group.

Specific examples of the repeating unit represented by Formula (BZ) willbe shown below, but the repeating unit is not limited thereto.

In the resin P, the content of the repeating unit having anacid-decomposable group (total content in a case where the resin Pcontains a plurality of kinds of the repeating units) with respect toall the repeating units in the resin P is preferably 5 to 80 mol %, morepreferably 5 to 75 mol %, and even more preferably 10 to 65 mol %.

The resin P may contain a repeating unit represented by Formula (V) orFormula (VI).

In the formula, R₆ and R₇ each independently represent a hydrogen atom,a hydroxy group, a linear, branched, and cyclic alkyl group having 1 to10 carbon atoms, an alkoxy group, an acyloxy group, a cyano group, anitro group, an amino group, a halogen atom, an ester group (—OCOR or—COOR: R represents an alkyl group having 1 to 6 carbon atoms or afluorinated alkyl group), or a carboxyl group.

n₃ represents an integer of 0 to 6.

n₄ represents an integer of 0 to 4.

X⁴ represents a methylene group, an oxygen atom, or a sulfur atom.

Specific examples of the repeating unit represented by Formula (V) orFormula (VI) will be shown below, but the present invention is notlimited thereto.

The resin P may further contain a repeating unit having a silicon atomon a side chain. Examples of the repeating unit having a silicon atom ona side chain include a (meth)acrylate-based repeating unit having asilicon atom, a vinyl-based repeating unit having a silicon atom, andthe like. Typically, the repeating unit having a silicon atom on a sidechain is a repeating unit having a silicon atom-containing group on aside chain. Examples of the silicon atom-containing group include atrimethylsilyl group, a triethylsilyl group, a triphenylsilyl group, atricyclohexylsilyl group, a tristrimethylsiloxysilyl group, atristrimethylsilyl silyl group, a methyl bistrimethylsilyl silyl group,a methyl bistrimethylsiloxysilyl group, a dimethyltrimethylsilyl silylgroup, a dimethyl trimethylsiloxysilyl group, cyclic or linearpolysiloxane shown below, a cage-like, ladder-like, or randomsilsesquioxane structure, and the like. In the Formulas, R and R′ eachindependently represent a monovalent substituent. * represents a bondingsite.

As the repeating unit having the aforementioned group, for example, arepeating unit derived from an acrylate or methacrylate compound havingthe aforementioned group or a repeating unit derived from a compoundhaving the aforementioned group and a vinyl group is preferable.

It is preferable that the repeating unit having a silicon atom ispreferably a repeating unit having a silsesquioxane structure. In a casewhere the repeating unit has a silsesquioxane structure, in forming anultrafine pattern (for example, a line width equal to or smaller than 50nm) having a cross-sectional shape with a high aspect ratio (forexample, film thickness/line width is equal to or greater than 3), anextremely excellent collapse performance can be demonstrated.

Examples of the silsesquioxane structure include a cage-likesilsesquioxane structure, a ladder-like silsesquioxane structure, and arandom silsesquioxane structure. Among these, a cage-like silsesquioxanestructure is preferable.

The cage-like silsesquioxane structure is a silsesquioxane structurehaving a cage-like skeleton. The cage-like silsesquioxane structure maybe a complete cage-like silsesquioxane structure or an incompletecage-like silsesquioxane structure, but is preferably a completecage-like silsesquioxane structure.

The ladder-like silsesquioxane structure is a silsesquioxane structurehaving a ladder-like skeleton.

The random silsesquioxane structure is a silsesquioxane structure havinga random skeleton.

The cage-like silsesquioxane structure is preferably a siloxanestructure represented by Formula (S).

In Formula (S), R represents a monovalent organic group. A plurality ofR's may be the same as or different from each other.

The organic group is not particularly limited, and specific examplesthereof include a hydroxy group, a nitro group, a carboxy group, analkoxy group, an amino group, a mercapto group, a blocked mercapto group(for example, a mercapto group blocked (protected) by an acyl group), anacyl group, an imide group, a phosphino group, a phosphinyl group, asilyl group, a vinyl group, a hydrocarbon group which may have aheteroatom, a (meth)acryl group-containing group, an epoxygroup-containing group, and the like.

Examples of the heteroatom in the hydrocarbon group which may have aheteroatom include an oxygen atom, a nitrogen atom, a sulfur atom, aphosphorus atom, and the like.

Examples of the hydrocarbon group which may have a heteroatom include analiphatic hydrocarbon group, an aromatic hydrocarbon group, a groupobtained by combining these, and the like.

The aliphatic hydrocarbon group may be any of a linear, branched, orcyclic aliphatic hydrocarbon group. Specific examples of the aliphatichydrocarbon group include a linear or branched alkyl group (particularlyhaving 1 to 30 carbon atoms), a linear or branched alkenyl group(particularly having 2 to 30 carbon atoms), a linear or branched alkynylgroup (particularly having 2 to 30 carbon atoms), and the like.

Examples of the aromatic hydrocarbon group include an aromatichydrocarbon group having 6 to 18 carbon atoms such as a phenyl group, atolyl group, a xylyl group, or a naphthyl group.

In a case where the resin P has the repeating unit having a silicon atomon a side chain, the content of the repeating unit with respect to allthe repeating units in the resin P is preferably 1 to 30 mol %, morepreferably 5 to 25 mol %, and even more preferably 5 to 20 mol %.

The weight-average molecular weight of the resin P that is measured bygel permeation chromatography (GPC) and expressed in terms ofpolystyrene is preferably 1,000 to 200,000, more preferably 3,000 to20,000, and even more preferably 5,000 to 15,000. In a case where theweight-average molecular weight is 1,000 to 200,000, it is possible toprevent the deterioration of heat resistance and dry etching resistance,to prevent the deterioration of developability, and to prevent filmforming properties from deteriorating due to the increase in viscosity.

The dispersity (molecular weight distribution) is generally 1 to 5,preferably 1 to 3, more preferably 1.2 to 3.0, and even more preferably1.2 to 2.0.

The content of the resin P in the total solid content of the resistcomposition is preferably 50% to 99.9% by mass, and more preferably 60%to 99.0% by mass.

In the resist composition, one kind of resin P may be used singly, ortwo or more kinds of resins P may be used in combination.

(Photoacid Generator)

It is preferable that the resist composition contain a photoacidgenerator. As the photoacid generator, known photoacid generators can beused without particular limitation.

The content of the photoacid generator in the resist composition is notparticularly limited. The content of the photoacid generator withrespect to the total solid content of the resist composition ispreferably 0.1% to 20% by mass, and more preferably 0.5% to 20% by mass.One kind of photoacid generator may be used singly, or two or more kindsof photoacid generators may be used in combination. In a case where twoor more kinds of photoacid generators are used in combination, the totalcontent thereof is preferably within the above range.

Examples of the photoacid generator include the compounds described inJP2016-057614A, JP2014-219664A, JP2016-138219A, and JP2015-135379A.

(Quencher)

The resist composition may contain a quencher (acid diffusion controlagent). As the quencher, known quenchers can be used without particularlimitation.

The quencher is, for example, a basic compound and has a function ofinhibiting the acid-decomposable resin from being unintentionallydecomposed in an unexposed area by the acid spread from an exposed area.

The content of the quencher in the resist composition is notparticularly limited. The content of the quencher with respect to thetotal solid content of the resist composition is preferably 0.1% to 15%by mass, and more preferably 0.5% to 8% by mass with. One kind ofquencher may be used singly, or two or more kinds of quenchers may beused in combination. In a case where two or more kinds of quenchers areused in combination, the total content thereof is preferably within theabove range.

Examples of the quencher include the compounds described inJP2016-057614A, JP2014-219664A, JP2016-138219A, and JP2015-135379A.

(Hydrophobic Resin)

The resist composition may contain a hydrophobic resin.

It is preferable to design the hydrophobic resin such that the resin islocalized within the surface of a resist film. However, unlike asurfactant, the hydrophobic resin does not need to have a hydrophilicgroup in a molecule and may not make a contribution to the homogeneousmixing of a polar substance with a nonpolar substance.

The addition of the hydrophobic resin brings about effects such as thecontrol of static and dynamic contact angle formed between water and theresist film surface and the inhibition of outgas.

From the viewpoint of localization within the surface layer of a film,the hydrophobic resin preferably has any one or more kinds of groupsamong “fluorine atom”, “silicon atom”, and “CH₃ partial structureincluded in a side chain portion of the resin”, and more preferably hastwo or more kinds of groups among the above. Furthermore, it ispreferable that the hydrophobic resin has a hydrocarbon group having 5or more carbon atoms. These groups may be positioned in the main chainof the resin or may substitute a side chain of the resin.

In a case where the hydrophobic resin contains a fluorine atom and/or asilicon atom, the fluorine atom and/or the silicon atom in thehydrophobic resin may be contained in the main chain or the side chainof the resin.

In a case where the hydrophobic resin contains a fluorine atom, as apartial structure having the fluorine atom, a fluorine atom-containingalkyl group, a fluorine atom-containing cycloalkyl group, or a fluorineatom-containing aryl group is preferable.

The fluorine atom-containing alkyl group (preferably having 1 to 10carbon atoms and more preferably having 1 to 4 carbon atoms) is a linearor branched alkyl group in which at least one hydrogen atom issubstituted with a fluorine atom and which may further have asubstituent other than a fluorine atom.

The fluorine atom-containing cycloalkyl group is a monocyclic orpolycyclic cycloalkyl group in which at least one hydrogen atom issubstituted with a fluorine atom and which may further have asubstituent other than a fluorine atom.

Examples of the fluorine atom-containing aryl group include an arylgroup in which at least one hydrogen atom is substituted with a fluorineatom, such as a phenyl group or a naphthyl group. The fluorineatom-containing aryl group may further have a substituent other than afluorine atom.

Examples of the repeating unit having a fluorine atom or a silicon atominclude the repeating units exemplified in paragraph “0519” ofUS2012/0251948A1.

As described above, it is also preferable that the hydrophobic resincontains a CH₃ partial structure in a side chain portion.

Herein, the CH₃ partial structure that the side chain portion of thehydrophobic resin has includes a CH₃ partial structure that an ethylgroup, a propyl group, or the like has.

A methyl group directly bonded to the main chain of the hydrophobicresin (for example, an α-methyl group of a repeating unit having amethacrylic acid structure) makes a small contribution to the surfacelocalization of the hydrophobic resin due to the influence of the mainchain. Accordingly, such a methyl group is not included in the CH₃partial structure.

Regarding the hydrophobic resin, the description in paragraphs “0348” to“0415” of JP2014-010245A can be referred to, and the entire contentsthereof are incorporated into the present specification.

As the hydrophobic resin, in addition to the above resins, the resinsdescribed in JP2011-248019A, JP2010-175859A, and JP2012-032544A can alsobe preferably used.

Examples of the hydrophobic resin include resins represented by Formula(1b) to Formula (5b).

In a case where the resist composition contains the hydrophobic resin,the content of the hydrophobic resin with respect to the total solidcontent of the composition is preferably 0.01% to 20% by mass, and morepreferably 0.1% to 15% by mass.

(Solvent)

The resist composition may contain a solvent. As the solvent, knownsolvents can be used without particular limitations.

The solvent contained in the resist composition may be the same as ordifferent from the organic solvent contained in the pre-wet liquid.

The chemical liquid supplied by the present supply method can be used asa solvent contained in the resist composition.

The content of the solvent in the resist composition is not particularlylimited. The resist composition preferably contains the solvent suchthat the total solid content of the resist composition is adjusted to0.1% to 20% by mass, and more preferably contains the solvent such thatthe total solid content of the resist composition is adjusted to 0.5% to10% by mass. One kind of solvent may be used singly, or two or morekinds of solvents may be used in combination. In a case where two ormore kinds of solvents are used in combination, the total contentthereof is preferably within the above range.

Examples of the solvent include the solvents described inJP2016-057614A, JP2014-219664A, JP2016-138219A, and JP2015-135379A.

(Other Additives)

As necessary, the resist composition may additionally contain asurfactant, an acid proliferation agent, a dye, a plasticizer, aphotosensitizer, a light absorbing agent, an alkali-soluble resin otherthan the above resins, and/or a dissolution inhibitor.

In order to form a resist film (resist composition film) on a substrateby using the resist composition, a resist composition is prepared bymeans of the dissolving the aforementioned components in a solvent andthe like and filtered using a filter as necessary, and then thesubstrate (pre-wetted substrate) is coated with the resist composition.The pore size of the filter is preferably 0.1 μm or less, morepreferably 0.05 μm or less, and even more preferably 0.03 μm or less.The filter is preferably made of polytetrafluoroethylene, polyethylene,or nylon.

By an appropriate coating method such as spin coating, the substrate iscoated with the resist composition. Then, the resist composition withwhich the substrate is coated is dried to form a resist film.

As a drying method, a method of heating and drying is used. The heatingcan be performed by a unit comprising a general exposure/developmentmachine or the like, or may be performed using a hot plate or the like.

The heating temperature is preferably 80° C. to 180° C., more preferably80° C. to 150° C., even more preferably 80° C. to 140° C., andparticularly preferably 80° C. to 130° C. The heating time is preferably30 to 1,000 seconds, more preferably 60 to 800 seconds, and even morepreferably 60 to 600 seconds.

The film thickness of the resist film is, for example, 1 to 200 nm, andpreferably 10 to 100 nm.

In the resist film forming method and/or the pattern forming method, anoverlayer film (topcoat film) may be formed as the overlayer of theresist film. The overlayer film can be formed using, for example, acomposition for forming an overlayer film containing a hydrophobicresin, a photoacid generator, and a basic compound.

<(C) Exposure Step>

The exposure step is a step of exposing the resist film. As the methodof exposing the resist film, known methods can be used withoutparticular limitation.

Examples of the method of exposing the resist film include a method ofirradiating the resist film with actinic rays or radiation through apredetermined mask. In a case where the method of irradiating the resistfilm with electron beams is used, the resist film may be irradiatedwithout the intervention of a mask (this is also called “direct imaging”in some cases)

The actinic rays or the radiation used for exposure is not particularlylimited, and examples thereof include a KrF excimer laser, an ArFexcimer laser, extreme ultraviolet (EUV), an electron beam (EB), and thelike. Among these, extreme ultraviolet or an electron beam ispreferable. The exposure may be immersion exposure.

(PEB step)

It is preferable that the aforementioned pattern forming methodadditionally includes a Post Exposure Bake (PEB) step of baking theresist film obtained after exposure before the exposure step and thedevelopment step. By the baking, the reaction in the exposed portion isaccelerated, and either or both of sensitivity and pattern shape arefurther improved.

The heating temperature is preferably 80° C. to 150° C., more preferably80° C. to 140° C., and even more preferably 80° C. to 130° C.

The heating time is preferably 30 to 1,000 seconds, more preferably 60to 800 seconds, and even more preferably 60 to 600 seconds.

The heating can be performed by a unit comprising a generalexposure⋅development machine, or may be performed using a hot plate orthe like.

<(D) Development Step>

The development step is a step of developing the exposed resist film(hereinafter, referred to as “resist film obtained after exposure” aswell) by using a developer.

As the development method, known development methods can be used withoutparticular limitation. Examples of the development method includedipping method, a puddle method, a spray method, a dynamic dispensemethod, and the like.

Furthermore, the aforementioned pattern forming method may additionallyhave a step of substituting the developer with another solvent to stopthe development after the development step.

The development time is not particularly limited, but is preferably 10to 300 seconds in general and more preferably 10 to 120 seconds. Thetemperature of the developer is preferably 0° C. to 50° C., and morepreferably 15° C. to 35° C. In the pattern forming method, thedevelopment step may be performed at least once or multiple times.

(Developer)

As the developer, known developers can be used without particularlimitation. Examples of the developer include an alkaline developer anda developer containing an organic solvent (organic developer).

The chemical liquid supplied by the present supply method can be used asan organic solvent contained in an organic developer.

In the development step, both the development using a developercontaining an organic solvent and development using an alkalinedeveloper may be performed (so-called double development may beperformed).

<(E) Rinsing Step>

It is preferable that the aforementioned pattern forming methodadditionally includes a rinsing step after the development step.

The rinsing step is a step of washing the wafer, which comprises theresist film obtained after development, by using a rinsing solution.

As the washing method, known washing methods can be used withoutparticular limitation. Examples of the washing method include a rotationjetting method, a dipping method, a spray method, and the like.

Among these, it is preferable to use the rotation jetting method inwhich the wafer is washed and then rotated at a rotation speed of 2,000to 4,000 rpm such that the rinsing liquid is removed from the substrate.

The rinsing time is preferably 10 to 300 seconds, more preferably 10 to180 seconds, and even more preferably 20 to 120 seconds. The temperatureof the rinsing liquid is preferably 0° C. to 50° C., and more preferably15° C. to 35° C.

(Rinsing Liquid)

In a case where the wafer comprising the resist film is rinsed after thedevelopment using an alkaline developer, as the rinsing liquid, purewater is preferable. The rinsing liquid may be pure water containing asurfactant.

In a case where a wafer comprising a resist film is rinsed afterdevelopment using an organic developer, as the rinsing liquid, a rinsingliquid containing an organic solvent is preferable. As the organicsolvent contained in the rinsing liquid, for example, at least one kindof organic solvent is preferable which is selected from the groupconsisting of a hydrocarbon-based solvent, a ketone-based solvent, anester-based solvent, an alcohol-based solvent, an amide-based solvent,and an ether-based solvent, at least one kind of organic solventselected from the group consisting of a hydrocarbon-based solvent, anether-based solvent, and a ketone-based solvent is more preferable, andat least one kind of organic solvent selected from the group consistingof a hydrocarbon-based solvent and an ether-based solvent is even morepreferable.

It is preferable that the chemical liquid supplied by the present supplymethod be used as the rinsing liquid.

In a case where the developer containing an organic solvent is used inthe development step, the aforementioned pattern forming method may havethe rinsing step after the development step. However, from the viewpointof throughput (productivity), the pattern forming method may not havethe rinsing step.

As the pattern forming method that does not have a rinsing step, forexample, the description in paragraphs “0014” to “0086” ofJP2015-216403A can be cited, and the contents thereof are incorporatedinto the present specification.

As the rinsing solution, methyl isobutyl carbinol (MIBC) or the sameliquid (particularly, butyl acetate) as the developer is alsopreferable.

<Other Steps>

The aforementioned pattern forming method may have other steps inaddition to the steps described above. Examples of those other stepsinclude a washing step using a supercritical fluid, a heating step, andthe like.

The pattern forming method may also have a resist underlayerfilm-forming step of forming a resist underlayer film by using acomposition for forming a resist underlayer film on the substrate havingundergone the pre-wetting step. The resist underlayer film-forming stepcan be performed according to the method described in (B) resist filmforming step described above. In addition, the pre-wetting stepperformed before the resist underlayer film-forming step can beperformed according to the method described in (A) pre-wetting stepdescribed above.

(Removing Step Using Supercritical Fluid)

A removing step using a supercritical fluid is a step of removing thedeveloper and/or the rinsing liquid having adhered to the patternsurface by using a supercritical fluid after the development treatmentand/or the rinsing treatment.

(Heating Step)

The heating step is a step of heating the resist film to remove thesolvent remaining in the pattern after the development step, the rinsingstep, or the removing step using a supercritical fluid.

The heating temperature is not particularly limited, but is preferably40° C. to 160° C., more preferably 50° C. to 150° C., and even morepreferably 50° C. to 110° C.

The heating time is not particularly limited, but is preferably 15 to300 seconds, and more preferably 15 to 180 seconds.

(BARC Composition Coating Step)

The pattern forming method may have a step of coating the wafer with abottom of anti-reflection coating (BARC) composition before (B) resistfilm forming step. In addition, the BARC composition coating step mayfurther have a step of removing the BARC composition with which the edgepart (end part) of the wafer is unintentionally coated.

The chemical liquid can also be suitably used for other uses in additionto the manufacturing of semiconductor devices. The chemical liquid canbe used as a developer or a rinsing liquid of polyimide, a resist for asensor, a resist for a lens, and the like.

The chemical liquid can also be used as a solvent for medical uses orfor washing. Particularly, the chemical liquid can be suitably used forwashing members such as a container, a pipe, and a substrate (forexample, a wafer, glass, or the like).

EXAMPLES

Hereinafter, the present invention will be more specifically describedbased on examples. The materials, the amount and proportion thereofused, the details of treatments, the procedure of treatments, and thelike shown in the following examples can be appropriately modified aslong as the gist of the present invention is maintained. Therefore, thescope of the present invention is not limited to the following examples.

In various measurements, in a case where a component to be measured wasoutside the range that can be measured by each measurement apparatus(for example, in a case where the component is equal to or less than themeasurement limit), by using a glass instrument thoroughly washed withthe object to be measured (chemical liquid), the object to be measuredis measured after being concentrated or diluted.

A supply device was prepared which comprises the storage tank 11, thegas pipe 12, the pipe line 13, the intermediate tank 14, the pipe line15, the discharge unit 16, and the pump 17 and the filter unit 20disposed on the pipe line 15 as shown in FIG. 1 . In addition, a gasfilter (“Wafergard III NF-750 in-line gas filter” manufactured byEntegris Inc.) was disposed on the upstream side of the storage tank 11of the gas pipe 12.

[Raw Material]

(Pumping Gas)

In each of examples and comparative example, as a gas for feeding of achemical liquid (pumping gas), the following gases were used.

-   -   Argon (Ar)    -   Nitrogen (N₂)    -   Helium (He)

(Organic Solvent)

In each of examples and comparative examples, as a chemical liquid, thefollowing organic solvents were used.

-   -   Propylene glycol monomethyl ether acetate (PGMEA)    -   Hexane    -   4-Methyl-2-pentanol (MIBC)    -   1-Hexanol    -   Isopropanol (IPA)    -   Propylene glycol monoethyl ether (PGME)    -   Ethyl lactate (EL)    -   Butyl acetate (nBA)    -   Propylene carbonate    -   Ethyl propionate    -   Isoamyl acetate    -   2-Heptanone (MAK)    -   Methyl ethyl ketone (MEK)    -   Cyclohexanone    -   Cyclopentanone

(Content of Specific Metal Components)

The content of each type of metal component (metal ions and metalparticles) in the chemical liquid was measured under the followingconditions by using ICP-MS (“Agilent 8800 triple quadrupole ICP-MS (forsemiconductor analysis, option #200)”).

As a sample introduction system, a quartz torch, a coaxialperfluoroalkoxyalkane (PFA) nebulizer (for self-suction), and a platinuminterface cone were used. The measurement parameters of cool plasmaconditions are as follows.

-   -   Output of Radio Frequency (RF) (W): 600    -   Flow rate of carrier gas (L/min): 0.7    -   Flow rate of makeup gas (L/min): 1    -   Sampling depth (mm): 18

(Moisture Content)

The moisture content in the chemical liquid was measured using a KarlFischer moisture titrator (trade name “MKC-710M”, manufactured by KYOTOELECTRONICS MANUFACTURING CO., LTD., Karl Fischer coulometric titrationtype)

(Content of Dioctyl Phthalate)

The content of dioctyl phthalate (DOP) in the chemical liquid wasmeasured under the following conditions by using a gaschromatography-mass spectroscopy (trade name “GCMS-2020”, manufacturedby Shimadzu Corporation).

Capillary column: InertCap 5MS/NP 0.25 mmI.D. ‘30 m df=0.25 μm

Sample introduction method: slit 75 kPa constant pressure

Vaporizing chamber temperature: 230° C.

Column oven temperature: 80° C. (2 min)-500° C. (13 min) heating rate15° C./min

Carrier gas: helium

Septum purge flow rate: 5 mL/min

Split ratio: 25:1

Interface temperature: 250° C.

Ion source temperature: 200° C.

Measurement mode: Scan m/z=85 to 1,000

Amount of sample introduced: 1 μL

(Filter)

In each of examples and comparative examples, a filter constituted withthe following material was used.

-   -   Polytetrafluoroethylene (PTFE)    -   Polyethylene (PE)    -   Nylon

[Preparation of Chemical Liquid]

A commercially available organic solvent was prepared and purified usingthe following purification device, thereby preparing a chemical liquidused in each of examples and comparative examples.

First, a purification device was prepared which comprises container, adischarge unit, a pipe connecting the container to the discharge unit, afiltering device disposed on the pipe, and a return pipe connecting thecontainer to a pipe positioned on the downstream side from the filteringdevice. The filtering device is composed of a plurality of filter unitsarranged in series on the pipe and does not have an adjusting valve. Thefiltering device comprised, for example, a filter unit having thefollowing filters in order from the upstream side (primary side).

-   -   Polypropylene filter (pore diameter: 200 nm, porous membrane)    -   Polyfluorocarbon filter having an ion exchange group (pore        diameter: 100 nm, fiber membrane consisting of a polymer of PTFE        and polyethylene sulfonate (PES))    -   Nylon filter (pore diameter: 3 nm, fiber membrane)

The return pipe has a function of returning the organic solvent that haspassed through the filtration device to the container.

The liquid contact portion of the purification device was thoroughlywashed with an organic solvent, and then the chemical liquid wasprepared using the washed purification device.

After the container was filled with the organic solvent, a pump disposedon a pipe connecting the container to the filtration device was operatedto send the organic solvent from the container to the filtration device.The organic solvent was filtered by the filter unit in the filtrationdevice, and then the filtered organic solvent was returned to thecontainer through the return pipe. The filtration using the filter unitand the return of the filtered organic solvent were repeated, and thenthe filtered organic solvent was discharged from the discharge unit,thereby obtaining a chemical liquid used in each of examples andcomparative examples.

In addition, for each of examples and comparative examples, the type andnumber of filters that the filtering device comprises in the filtrationdevice in the aforementioned filtration treatment and the number oftimes the filtration is repeated were appropriately changed, therebypreparing chemical liquids having the compositions shown in Table 1.

Example 1

A filter cartridge having a filter having a pore diameter of 2 nm washoused in a filter unit 20 disposed on the pipe line 15 of the supplydevice 10. The material (filter medium) constituting the filter waspolytetrafluoroethylene (PTFE).

The content of each of the specific metal components, moisture, anddioctyl phthalate in each chemical liquid prepared by the abovepreparation method was measured by the above measuring method, and thenthe chemical liquid is stored in the storage tank 11.

As a raw material gas, Ar was sent into the gas pipe 12 and passedthrough a gas filter to prepare a pumping gas. The obtained pumping gaswas introduced into the storage tank 11 from the top of the storage tank11 connected to the gas pipe 12. In this way, the pressure of the gasaccumulated in the head space of the upper part of the storage tank 11was increased such that the surface of the chemical liquid stored in thestorage tank 11 was pressurized. By the pressure difference between theinside of the storage tank 11 and the inside of the intermediate tank 14generated by the pressurization, the chemical liquid stored in thestorage tank 11 was sent (pumped) to the intermediate tank 14 throughthe pipe line 13. Then, the pump 17 disposed on the pipe line 15connecting the intermediate tank 14 to the discharge unit 16 wasoperated such that the chemical liquid stored in the intermediate tank14 was discharged from the discharge unit 16. At this time, by passingthe chemical liquid through the filter unit 20 disposed in the pipe line15, a filtration treatment was performed on the chemical liquid as apurification step.

Examples 2 to 65 and Comparative Examples 1 to 5

A purified chemical liquid was obtained by supplying the chemical liquidaccording to the same method described in Example 1, except that thepumping gas, chemical liquid, and filter described in Table 1 were used.

The chemical liquid obtained in each of examples and comparativeexamples was evaluated as below.

[Evaluation]

(Evaluation of Elution Amount of Impurity)

For the supply method of each of examples and comparative examples, thecontent of an organic impurity in the chemical liquid was measured bythe following method. In this way, the amount of an organic impurityeluted into the chemical liquid from the liquid contact portion of thepipe line or the like of the supply device in each supply method wasmeasured.

First, a silicon oxide film substrate having a diameter of 300 mm wasprepared. By using a wafer surface inspection device (Surfscan SPS;manufactured by KLA-Tencor), the number of organic residues having adiameter of 19 nm or more present on the substrate was measured (themeasured number of organic residues is adopted as an initial value).

Then, the substrate was set in a spin jet device, and in a state wherethe substrate was being rotated, the chemical liquid not yet being usedin each supply method was jetted to the surface of the substrate at aflow rate of 1 mL/s.

Thereafter, the substrate was spin-dried. By using the aforementionedinspection device, the number of organic residues having a diameter of19 nm or more present on the substrate having been coated with thechemical liquid was measured (the measured number of organic residues isadopted as a measured value). A difference between the initial value andthe measured value (measured value−initial value) was calculated andadopted as an organic impurity amount A1 derived from the chemicalliquid not yet being used in each supply method.

Based on the coordinate data calculated by the aforementioned inspectiondevice, for defects newly increased after the substrate was coated withthe chemical liquid, elemental analysis was performed by energydispersive X-ray spectrometry (EDX) by using a defect analyzer (SEMVision G6; manufactured by Applied Materials, Inc.). By this method, ithas been confirmed that the particles measured as an organic impurity donot contain a metal component.

A sample for measuring an elution amount of each of examples andcomparative examples was obtained by the same method as the supplymethod of each of examples and comparative examples described above,except that the filter cartridge having a filter was not housed in thefilter unit, and a chemical liquid purification step using a filter wasnot performed.

For each sample, the initial value and the measured value were measuredaccording to the same method as described above, and it has beenconfirmed that the measured particles are an organic impurity that doesnot contain a metal component. The difference between the obtainedinitial value and measured value (measured value−initial value) wascalculated and adopted as an organic impurity amount A2 derived fromeach sample.

From the amount of organic impurity amount A1 derived from the chemicalliquid not yet being supplied and the organic impurity amount A2 derivedfrom the sample, an elution amount of impurities (number/wafer) in thesupply method of each of examples and comparative examples wascalculated using Formula (A1−A2). The calculated elution amount ofimpurities is shown in Table 1.

The smaller the elution amount of impurities, the further the elutioninto the chemical liquid from the liquid contact portion of the pipeline or the like of the supply device is suppressed by the supplymethod.

(Evaluation of Removing Performance of Filter)

For the supply method of each of examples and comparative examples, theremoving performance of the filter in the purification step of filteringthe chemical liquid was evaluated by the following method.

For Examples 1 to 65 and Comparative Examples 1 to 5, by using thechemical liquid obtained by the aforementioned supply method having thechemical liquid purification step using a filter, the amount of anorganic impurity was measured in the same manner as in theaforementioned test for evaluating the elution amount of impurities.

That is, for the chemical liquid of each of examples and comparativeexamples, the initial value and the measured value were measuredaccording to the same method as described above, and it has beenconfirmed that the measured particles are an organic impurity that doesnot contain a metal component. The difference between the obtainedinitial value and measured value (measured value−initial value) wascalculated and adopted as an organic impurity amount A3 derived fromeach chemical liquid.

From the organic impurity amount A2 derived from the sample obtained bythe supply method that does not have the purification step and anorganic impurity amount A3 derived from the chemical liquid obtained bythe supply method having the purification step, a removal rate (%) ofimpurities removed by the purification step that each supply method haswas calculated using Formula ((A2−A3)/A2). The calculated removal rateof impurities (filter removal rate) is shown in Table 1.

The higher the filter removal rate, the higher the organic impurityremoving performance of the purification step that the supply methodhas.

Table 1 shows the composition of the pumping gas, the composition of thechemical liquid, and the filter used in each of examples and comparativeexamples and the evaluation results.

The column of “Type” of “Pumping gas” in Table 1 shows the type ofpumping gas used in each of examples and comparative examples.

The column of “Gas filter” shows whether or not the supply device usedin each of examples and comparative examples has a gas filter. “Present”written in the column of Gas filter means that a pumping gas wasprepared (purified) by passing a gas through a gas filter provided onthe gas pipe. “Absent” written in the column of Gas filter means that apumping gas shown in Table 1 was prepared by purification in advancewithout performing the purification of the pumping gas in the supplydevice.

The column of “Moisture content (ppm)” shows the content (unit: ppm bymass) of moisture contained in the pumping gas used in each of examplesand comparative examples.

The “purity” column indicates the purity of the pumping gas used in eachExample and each Comparative Example. That is, “2N”, “3N”, and “5N”written in the column of “Purity” mean that the purity of the usedpumping gas was 99% by volume (2N), 99.9% by volume (3N), and 99.999% byvolume (5N), respectively.

The column of “Organic solvent” of “Chemical liquid” in Table 1 showsthe type of organic solvent used in each of examples and comparativeexamples. In all the examples and comparative examples, the content ofthe organic solvent contained in the chemical liquid was 99.5% by massor more.

The column of “Specific metal content (ppt)” shows the total content(unit: ppt by mass) of an Fe component (Fe particles and Fe ions), a Crcomponent (Cr particles and Cr ions), a Ni component (Ni particles andNi ions), and an Al component (Al particles Al ions) component) withrespect to the total mass of the chemical liquid.

The content of metal components other than the specific metal componentscontained in the chemical liquid used in each of examples was measured.As a result, in all the examples, the content of the aforementionedother metal components was 10 ppt by mass or less with respect to thetotal mass of the chemical liquid.

The column of “Moisture content (%)” shows the content of water (unit: %by mass) with respect to the total mass of the chemical liquid used ineach of examples and comparative examples.

The column of “DOP (ppb)” shows the content of dioctyl phthalate (unit:ppb by mass) with respect to the total mass of the chemical liquid usedin each of examples and comparative examples.

The column of “Material” of “Filter” in Table 1 shows the material ofthe filter medium constituting the filter used in the chemical liquidpurification step in the supply device, and the column of “Porediameter” shows the pore diameter of each filter.

TABLE 1 Evaluation result Chemical liquid Elution Pumping gas SpecificFilter amount of Filter Moisture metal Moisture Pore impurity removalGas content Organic content content DOP diameter (number/ rate Typefilter (ppm) Purity solvent (ppt) (%) (ppb) Material (nm) wafer) (%)Example 1 Ar Present 0.01 5N PGMEA 0.2 0.01 1 PTFE 2 36 99.0 Example 2N₂ Present 0.01 5N PGMEA 0.2 0.01 1 PTFE 2 57 95.8 Example 3 He Present0.01 5N PGMEA 40 0.01 1 PTFE 2 73 92.0 Example 4 N₂ Present 0.025 5NPGMEA 0.2 0.01 1 PTFE 2 61 93.0 Example 5 N₂ Present 0.45 5N PGMEA 0.20.01 1 PTFE 2 250 90.0 Example 6 N₂ Present 0.97 5N PGMEA 0.2 0.01 1PTFE 2 371 86.9 Example 7 N₂ Present 0.0044 5N PGMEA 0.2 0.01 1 PTFE 2357 88.2 Example 8 N₂ Present 0.03 5N PGMEA 52 0.01 1 PTFE 2 247 92.4Example 9 N₂ Present 0.5 5N PGMEA 24 0.01 1 PTFE 2 366 87.8 Example 10N₂ Present 1 5N PGMEA 48 0.01 1 PTFE 2 453 85.6 Example 11 N₂ Present0.009 5N PGMEA 48 0.01 1 PTFE 2 249 90.8 Example 12 N₂ Present 0.005 5NPGMEA 48 0.01 1 PTFE 2 250 89.4 Example 15 N₂ Present 0.00001 5N PGMEA0.28 0.01 1 PTFE 2 356 86.5 Example 14 N₂ Present 0.01 3N PGMEA 0.280.01 1 PTFE 2 356 93.7 Example 15 N₂ Present 0.01 2N PGMEA 0.28 0.01 1PTFE 2 356 88.5 Example 15 N₂ Present 0.01 5N PGMEA 55 0.01 1 PTFE 2 7295.2 Example 17 N₂ Present 0.01 5N PGMEA 62 0.01 1 PTFE 2 69 93.3Example 18 N₂ Present 0.01 5N PGMEA 400 0.01 1 PTFE 2 70 92.8 Example 19N₂ Present 0.01 5N PGMEA 409 0.01 1 PTFE 2 64 90.0 Example 20 N₂ Present0.01 5N PGMEA 631 0.01 1 PTFE 2 71 89.4 Example 21 N₂ Present 0.01 5NPGMEA 1150 0.01 1 PTFE 2 71 88.4 Example 22 N₂ Present 0.01 5N PGMEA1280 0.01 1 PTFE 2 56 81.8 Example 23 N₂ Present 0.01 5N PGMEA 0.16 0.011 PTFE 2 57 91.2 Example 24 N₂ Present 0.01 5N PGMEA 0.036 0.01 1 PTFE 256 86.1 Example 25 N₂ Present 0.01 5N PGMEA 0.06 0.01 1 PTFE 2 68 91.5

TABLE 2 Evaluation result Chemical liquid Elution Pumping gas SpecificFilter amount of Filter Moisture metal Moisture Pore impurity removalGas content Organic content content DOP diameter (number/ rate Typefilter (ppm) Purity solvent (ppt) (%) (ppb) Material (nm) wafer) (%)Example 26 N₂ Present 0.01 5N PGMEA 40 0.015 1 PTFE 2 57 93.7 Example 27N₂ Present 0.01 5N PGMEA 44 0.028 1 PTFE 2 63 92.3 Example 28 N₂ Present0.01 5N PGMEA 12 0.032 1 PTFE 2 62 89.0 Example 29 N₂ Present 0.01 5NPGMEA 44 0.0005 1 PTFE 2 72 88.2 Example 30 N₂ Present 0.01 5N PGMEA 160.0009 1 PTFE 2 71 91.2 Example 31 N₂ Present 0.01 5N PGMEA 44 0.01 5PTFE 2 60 92.5 Example 32 N₂ Present 0.01 5N PGMEA 48 0.01 10 PTFE 2 6291.8 Example 33 N₂ Present 0.01 5N PGMEA 52 0.01 11 PTFE 2 68 90.2Example 34 N₂ Present 0.01 5N PGMEA 52 0.01 0.009 PTFE 2 71 90.9 Example35 N₂ Present 0.01 5N PGMEA 52 0.01 0.001 PTFE 2 64 89.1 Example 36 N₂Present 0.01 5N PGMEA 52 0.01 0.0005 PTFE 2 62 85.3 Example 37 N₂Present 0.01 5N Hexane 0.05 0.01 1 PTFE 2 76 94.4 Example 38 N₂ Present0.01 5N MIBC 3 0.01 1 PTFE 2 60 94.3 Example 39 N₂ Present 0.01 5N1-Hexanol 5 0.01 1 PTFE 2 74 94.9 Example 40 N₂ Present 0.01 5N IPA 60.01 1 PTFE 2 52 95.9 Example 41 N₂ Present 0.01 5N PGME 12 0.01 1 PTFE2 64 94.1 Example 42 N₂ Present 0.01 5N EL 3 0.01 1 PTFE 2 64 95.8Example 43 N₂ Present 0.01 5N nBA 15 0.01 1 PTFE 2 71 94.7 Example 44 N₂Present 0.01 5N Propylene 1 0.01 1 PTFE 2 74 95.1 carbonate Example 45N₂ Present 0.01 5N Ethyl 0.2 0.01 1 PTFE 2 65 94.4 propionate Example 46N₂ Present 0.01 5N Isoamyl 0.9 0.01 1 PTFE 2 71 94.8 acetate Example 47N₂ Present 0.01 5N MAK 5 0.01 1 PTFE 2 71 95.2 Example 48 N₂ Present0.01 5N MEK 2 0.01 1 PTFE 2 71 95.7 Example 49 N₂ Present 0.01 5N Cyclo-1 0.01 1 PTFE 2 62 94.5 hexamone Example 50 N₂ Present 0.01 5N Cyclo- 10.01 1 PTFE 2 58 94.1 pentanone

TABLE 3 Evaluation result Chemical liquid Elution Pumping gas SpecificFilter amount of Filter Moisture metal Moisture Pore impurity removalGas content Organic content content DOP diameter (number/ rate Typefilter (ppm) Purity solvent (ppt) (%) (ppb) Material (nm) wafer) (%)Example 51 N₂ Present 0.01 5N PGMEA 4 0.01 1 PTFE 5 60 94.8 Example 52N₂ Present 0.01 5N PGMEA 4 0.01 1 PTFE 10 54 95.1 Example 53 N₂ Present0.01 5N PGMEA 4 0.01 1 PTFE 20 70 95.6 Example 54 N₂ Present 0.01 5NPGMEA 4 0.01 1 PTFE 50 67 94.4 Example 55 N₂ Present 0.01 5N PGMEA 40.01 1 PE 1 67 94.3 Example 56 N₂ Present 0.01 5N PGMEA 4 0.01 1 PE 3 5895.0 Example 57 N₂ Present 0.01 5N PGMEA 4 0.01 1 PE 5 56 94.4 Example58 N₂ Present 0.01 5N PGMEA 4 0.01 1 PE 10 69 95.9 Example 59 N₂ Present0.01 5N PGMEA 4 0.01 1 PE 20 72 94.3 Example 60 N₂ Present 0.01 5N PGMEA4 0.01 1 PE 50 78 94.7 Example 61 N₂ Present 0.01 5N PGMEA 4 0.01 1 PP50 55 95.7 Example 62 N₂ Present 0.01 5N PGMEA 4 0.01 1 Nylon 5 72 95.7Example 63 N₂ Present 0.01 5N PGMEA 4 0.01 1 Nylon 20 63 94.2 Example 64N₂ Present 0.01 5N PGMEA 16 0.01 1 Absent — 69 0.0 Example 65 N₂ Absent1 5N PGMEA 48 0.01 1 PTFE 2 453 85.8 Comparative N₂ Present 1.1 5N PGMEA32 0.01 1 PTFE 2 860 78.5 Example 1 Comparative N₂ Present 1.5 5N PGMEA48 0.01 1 PTFE 2 1065 73.3 Example 2 Comparative N₂ Present 0.000089 5NPGMEA 8 0.01 1 PTFE 2 772 76.3 Example 3 Comparative N₂ Present 0.0000055N PGMEA 52 0.01 1 PTFE 2 973 70.3 Example 4 Comparative N₂ Present 3 5NPGMEA 4 0.01 1 PTFE 2 1364 63.7 Example 5

As shown in Table 1, it has been confirmed that the chemical liquidsupply method of Examples 1 to 65 is more effective in reducing theamount of an organic impurity eluted into the chemical liquid from apipe line, compared to the chemical liquid supply method of ComparativeExamples 1 to 5.

EXPLANATION OF REFERENCES

-   -   10: supply device    -   11: storage tank    -   12: gas pipe    -   12 a: gas introduction port    -   13, 15: pipe line    -   14: intermediate tank    -   16: discharge port    -   17: pump    -   20: filter unit    -   21: gas filter

What is claimed is:
 1. A chemical liquid supply method of supplying achemical liquid containing an organic solvent through a pipe line thatis provided in an apparatus for semiconductor devices, the chemicalliquid supply method comprising: a gas pumping step of sending thechemical liquid by pressurization using a gas, wherein a moisturecontent in the gas is 0.00001 to 1 ppm by mass with respect to a totalmass of the gas.
 2. The chemical liquid supply method according to claim1, wherein a purity of the gas is 99.9% by volume or more.
 3. Thechemical liquid supply method according to claim 1, wherein the moisturecontent in the gas is 0.005 to 0.5 ppm by mass with respect to the totalmass of the gas.
 4. The chemical liquid supply method according to claim1, wherein the moisture content in the gas is 0.01 to 0.03 ppm by masswith respect to the total mass of the gas.
 5. The chemical liquid supplymethod according to claim 1, wherein a purity of the gas is 99.999% byvolume or more.
 6. The chemical liquid supply method according to claim1, wherein the gas includes at least one gas selected from the groupconsisting of nitrogen and argon.
 7. The chemical liquid supply methodaccording to claim 1, wherein the organic solvent is at least onecompound selected from the group consisting of propylene glycolmonomethyl ether, propylene glycol monoethyl ether, propylene glycolmonopropyl ether, propylene glycol monomethyl ether acetate, ethyllactate, methyl methoxypropionate, ethyl propionate, cyclopentanone,cyclohexanone, γ-butyrolactone, diisoamyl ether, butyl acetate, isoamylacetate, isopropanol, 4-methyl-2-pentanol, 1-hexanol, dimethylsulfoxide,n-methyl-2-pyrrolidone, diethylene glycol, ethylene glycol, dipropyleneglycol, propylene glycol, ethylene carbonate, propylene carbonate,sulfolane, cycloheptanone, 2-heptanone, methyl ethyl ketone, hexane, anda combination of these.
 8. The chemical liquid supply method accordingto claim 1, further comprising: a chemical liquid preparation step ofpreparing the chemical liquid in a storage tank that is in communicationwith the pipe line, wherein the gas pumping step is a step of sendingthe chemical liquid from the storage tank through the pipe line byintroducing the gas into the storage tank.
 9. The chemical liquid supplymethod according to claim 1, further comprising: a purification step offiltering the chemical liquid sent by the gas pumping step by using afilter.
 10. The chemical liquid supply method according to claim 9,wherein a total content of a Fe component, a Cr component, a Nicomponent, and an Al component in the chemical liquid filtered by thepurification step is 0.04 to 1,200 ppt by mass with respect to a totalmass of the chemical liquid.
 11. The chemical liquid supply methodaccording to claim 9, wherein a total content of a Fe component, a Crcomponent, a Ni component, and an Al component in the chemical liquidfiltered by the purification step is 0.2 to 400 ppt by mass with respectto a total mass of the chemical liquid.
 12. The chemical liquid supplymethod according to claim 9, wherein a total content of a Fe component,a Cr component, a Ni component, and an Al component in the chemicalliquid filtered by the purification step is 0.2 to 60 ppt by mass withrespect to a total mass of the chemical liquid.
 13. The chemical liquidsupply method according to claim 9, wherein a moisture content in thechemical liquid filtered by the purification step is 0.0005% to 0.03% bymass with respect to a total mass of the chemical liquid.
 14. Thechemical liquid supply method according to claim 9, wherein a moisturecontent in the chemical liquid filtered by the purification step is0.001% to 0.02% by mass with respect to a total mass of the chemicalliquid.
 15. The chemical liquid supply method according to claim 9,wherein a moisture content in the chemical liquid filtered by thepurification step is 0.001% to 0.01% by mass with respect to a totalmass of the chemical liquid.
 16. The chemical liquid supply methodaccording to claim 9, wherein a content of dioctyl phthalate in thechemical liquid filtered by the purification step is 0.001 to 10 ppb bymass with respect to a total mass of the chemical liquid.
 17. Thechemical liquid supply method according to claim 9, wherein a content ofdioctyl phthalate in the chemical liquid filtered by the purificationstep is 0.01 to 5 ppb by mass with respect to a total mass of thechemical liquid.
 18. The chemical liquid supply method according toclaim 9, wherein a content of dioctyl phthalate in the chemical liquidfiltered by the purification step is 0.01 to 1 ppb by mass with respectto a total mass of the chemical liquid.
 19. The chemical liquid supplymethod according to claim 1, further comprising: a gas purification stepof purifying a raw material gas by using a gas filter, wherein the gaspurified by the gas purification step is used in the gas pumping step.20. A pattern forming method comprising: a pre-wetting step of bringinga pre-wet liquid into contact with a substrate; a resist film formingstep of forming a resist film on the substrate by using a resistcomposition; a step of exposing the resist film; a development step ofdeveloping the exposed resist film by using a developer to form a resistpattern; and a rinsing step of bringing a rinsing liquid into contactwith the substrate on which the resist pattern is formed, wherein atleast one liquid selected from the group consisting of the pre-wetliquid, the developer, and the rinsing liquid is the chemical liquidsupplied by the supply method according to claim 1.